(CNN) Here's a look at Ukraine , the second-largest European country in area after Russia . It borders Moldova, Romania, Hungary, Slovakia, Poland, Belarus, Russia and the Black Sea in Eastern Europe.

About Ukraine

Population: 43,922,939 (July 2020 est.)

Median age: 41.2 years old

Capital: Kiev (Kyiv)

Ethnic Groups: Ukrainian 77.8%, Russian 17.3%, Belarusian 0.6%, Moldovan 0.5%, Crimean Tatar 0.5%, Bulgarian 0.4%, Hungarian 0.3%, Romanian 0.3%, Polish 0.3%, Jewish 0.2%, and other 1.8% (2001 est.)

GDP (purchasing power parity): $369.6 billion (2017 est.)

GDP per capita: $8,800 (2017 est.)

Unemployment: 9.2% (2017 est.)

Other Facts

Prior to the 20th century, Ukrainian territories were controlled at different times by Russia, Poland, Lithuania, Mongols, Cossacks and others.

From the 18th to 20th centuries, Russia and the Soviet Union carried out a program of Russification to discourage Ukrainian national identity.

Timeline

1917-1920 - Following the 1917 Russian Revolution and toward the end of Following the 1917 Russian Revolution and toward the end of World War I , Ukraine is briefly an independent nation.

1920s - Ukraine becomes part of the Union of Soviet Socialist Republics.

1921-1922 - A famine kills more than one million people.

1932-1933 - Soviet leader Joseph Stalin's policy of collectivization leads to the Great Famine (Holodomor) in which millions of Ukrainians die of starvation.

1941 - During During World War II , Germany invades Ukraine. More than six million Ukrainians, the great majority of them civilians, die in the war.

1944 - The Soviet Union regains control of Ukraine and expands its borders to include territory taken from Romania, Poland and Czechoslovakia.

July 16, 1990 - Ukraine declares sovereignty.

August 24, 1991 - Parliament declares independence, pending a referendum on December 1.

December 1, 1991 - The referendum for independence passes with 90% approval.

December 8, 1991 - Ukraine joins the new Commonwealth of Independent States, along with Russia and Belarus.

2004 - President Leonid Kuchma declines to run for a third term and endorses Prime Minister Viktor Yanukovych. President Leonid Kuchma declines to run for a third term and endorses Prime Minister Viktor Yanukovych. Russian President Vladimir Putin also supports Yanukovych's campaign.

September 2004 - Opposition candidate Viktor Yushchenko develops a mysterious illness which leaves his face pock-marked. Medical tests later show he is suffering from dioxin poisoning.

October 31, 2004 - In the first round of presidential elections, Yanukovych and Yushchenko both receive about 40% of the vote.

November 21, 2004 - Preliminary exit polls from the run-off election give Yushchenko a lead of 52% to Yanukovych's 43%, but Yanukovych is officially declared the winner. Independent election monitors allege fraud.

November 22, 2004 - Mass protests sweep the country, with demonstrators wearing orange, Yushchenko's campaign color. Activist Yulia Tymoshenko becomes a prominent figure of the pro-Western Orange Revolution.

December 3, 2004 - The Supreme Court rules the previous run-off election invalid and orders a new run-off.

December 26, 2004 - Yushchenko wins the election with about 52% of the vote and is sworn in as president a month later.

January 2005 - Yushchenko names Tymoshenko as prime minister.

September 2005 - Yushchenko fires his entire cabinet, including Tymoshenko.

January 2006 - Russian energy monopoly Russian energy monopoly Gazprom briefly cuts off natural gas supplies to Ukraine.

December 18, 2007 - Tymoshenko returns as prime minister.

January 2009 - Gazprom again cuts off supplies of natural gas to Ukraine over a payment dispute.

January 17, 2010 - Presidential elections are held. Yushchenko receives only 5% of the vote. Yanukovych receives 35% and Tymoshenko receives 25%, necessitating a run-off.

February 14, 2010 - In the run-off, Yanukovych wins 48.95% of the vote to Tymoshenko's 45.47%. Tymoshenko alleges fraud and is openly critical of Yanukovych. She loses her position as prime minister in March.

June 2010 - Ukraine's parliament abandons plans to join Ukraine's parliament abandons plans to join NATO

August 2011 - A court motion calls for Tymoshenko's arrest. The arrest is in connection to a 2009 gas contract negotiated when she was prime minister. Tymoshenko brushes off all charges against her as political, calling the trial a "farce."

November 21, 2013 - President Yanukovych backs out of a trade deal with the President Yanukovych backs out of a trade deal with the European Union due to pressure from Russia. Street protests begin in Kiev

December 17, 2013 - Putin agrees to buy $15 billion of Ukraine's debt and reduce the price of natural gas supplied to the country.

January 16, 2014 - Yanukovych signs laws restricting the right to protest. This leads to large numbers of protesters in Kiev and clashes with police. The law is repealed on January 28.

February 21, 2014 - Negotiations lead to a deal which reduces Yanukovych's powers as president and rolls back parts of the Constitution.

February 24, 2014 - An arrest warrant is issued for Yanukovych.

February 28, 2014 - Andrii Parubii, the Ukrainian chief of national security and defense, says the country's military and police forces have stopped Russian military forces from seizing two airports in Crimea.

March 1, 2014 - The upper house of the Russian parliament votes to send troops into Crimea on the same day the pro-Russian leader of Crimea, Sergey Aksyonov, asks Putin for help in maintaining peace.

March 2, 2014 - Ukrainian Prime Minister Arseniy Yatsenyuk says of Russian troops in the Crimean peninsula, "This is a red alert. This is not a threat. This is actually a declaration of war to my country."

March 3, 2014 - Ukrainian Ambassador Yuriy Sergeyev tells an emergency meeting of the Ukrainian Ambassador Yuriy Sergeyev tells an emergency meeting of the UN Security Council that Russia has used planes, boats and helicopters to flood Crimea with 16,000 troops in the past week.

March 4, 2014 - visits Ukraine and announces the United States will give Ukraine's new government a $1 billion loan guarantee. Senior US administration officials tell CNN this will help insulate the Ukrainian economy from the effects of reduced energy subsidies from Russia. US Secretary of State John Kerry visits Ukraine and announces the United States will give Ukraine's new government a $1 billion loan guarantee. Senior US administration officials tell CNN this will help insulate the Ukrainian economy from the effects of reduced energy subsidies from Russia.

March 6, 2014 - Crimea's parliament votes to hold a referendum on leaving Ukraine and becoming part of Russia.

March 16, 2014 - In the Crimean referendum, 96.7% vote in favor of leaving Ukraine and being annexed by Russia.

March 17, 2014 - US and EU officials announce sanctions on more than two dozen Russian officials and their allies in Crimea. Crimea's regional parliament applies to join with Russia, and in Moscow, Putin signs a decree that recognizes the independence and sovereignty of the Republic of Crimea.

March 18, 2014 - In Moscow, Putin signs an annexation pact with the prime minister of Crimea and the mayor of the city of Sevastopol.

March 18, 2014 - In response to masked gunmen killing a member of Ukraine's military, wounding another and placing the rest of the staff of a base in Crimea under arrest, the Defense Ministry authorizes its forces in Crimea to use weapons "to protect and preserve the life of Ukrainian soldiers."

March 22, 2014 - In Crimea, Russian special forces take control of Belbek Airbase, and pro-Russian self-defense forces take control of Novofederoskoe military base and a Ukrainian ship, the Slavutych.

April 15, 2014 - Acting President Oleksandr Turchynov tells the country's Parliament Acting President Oleksandr Turchynov tells the country's Parliament an "anti-terrorist operation" is under way in Ukraine's restive eastern Donetsk region. Tensions have soared in recent days in eastern Ukraine, where pro-Russian rebels have seized government and police buildings in as many as 10 towns and cities.

May 25, 2014 - , following preliminary exit polls that suggested he got 56% of the vote. Petro Poroshenko declares victory in Ukraine's presidential election , following preliminary exit polls that suggested he got 56% of the vote.

June 7, 2014 - Poroshenko is sworn in as Ukraine's new president.

June 27, 2014 - Ukraine signs a trade deal with the European Union, the same agreement that Yanukovych backed out of in 2013.

July 24, 2014 - Yatsenyuk and his cabinet announce their Yatsenyuk and his cabinet announce their resignation . A week later, parliament rejects his resignation.

September 20, 2014 - Ukraine and pro-Russian separatists agree to a ceasefire.

October 26, 2014 - Ukrainians vote in parliamentary elections. Ukrainian citizens in Russia-annexed Crimea and the eastern areas controlled by pro-Russian separatists do not participate in the elections because of ongoing violence. Poroshenko hails exit poll results and says the projected outcome gives "a powerful and irreversible backing to Ukraine's path to Europe."

January 26, 2015 - Poroshenko announces that Ukraine will ask The Hague tribunal to investigate alleged "crimes against humanity" in the conflict in eastern Ukraine.

February 12, 2015 - Peace talks end in a breakthrough: A ceasefire and an agreement for both sides to pull back heavy weapons. In March, heavy weapons are pulled back from the front lines, but the violence continues.

April 10, 2016 - Yatsenyuk announces he will resign.

September 28, 2016 - The Joint Investigation Team, a Dutch-led group of prosecutors gathering evidence for a potential criminal trial, says that it has concluded that Malaysia Airlines Flight 17 was downed over eastern Ukraine by a Buk missile brought in from Russia to a pro-Russian area of eastern Ukraine.

February 20, 2017 - A ceasefire aimed at ending the bloody fight between Ukrainian forces and Russian-backed separatists begins. The ceasefire is a renewed attempt to enforce the Minsk peace protocol -- an agreement that has repeatedly failed since it was first partially implemented in 2015.

March 23, 2017 - Denis Voronenkov, a onetime Communist member of Russia's lower house of parliament, dies after being shot outside a hotel in Kiev. Poroshenko calls the shooting a "Russian state terrorist act." Voronenkov, who fled to Ukraine in 2016, is the latest in a string of Putin and Russia's critics who were killed or injured under mysterious circumstances.

November 25, 2018 - The Ukrainian military says Russian boats opened fire on and seized three of its ships near Crimea, detaining 23 of its sailors and wounding at least three. The ships were planning to enter the Kerch Strait, a shared waterway of strategic importance for both countries. Russia claims the vessels illegally entered Russia's territorial waters and were carrying out dangerous maneuvers, according to Russian state news agency TASS.

November 26, 2018 - Ukrainian lawmakers vote to introduce martial law in the border areas with Russia. It will be introduced on November 28 and will last 30 days.

January 24, 2019 - Yanukovych is found guilty of treason by a Ukrainian court for helping Russia and for his attempts to quash demonstrations in 2014. He is sentenced in absentia to 13 years in prison.

May 1, 2019 - The New York Times publishes an article about allegations against The New York Times publishes an article about allegations against former Vice President Joe Biden and his son, Hunter Biden related to a Ukrainian energy company called Burisma Holdings. The younger Biden served on the board of Burisma and in 2016, his father pressured Ukraine to oust a prosecutor who had investigated the company. Rudy Giuliani, the personal lawyer of US President Donald Trump , tells the Times that he is looking into the matter on behalf of his client, indicating that the vice president's move was motivated by a desire to protect his son from criminal charges. Giuliani's claims are later undermined when Bloomberg reports that the Burisma investigation was "dormant" when Biden pressed the prosecutor to resign.

May 7, 2019 - The US Embassy in Kiev announces that Ambassador Marie Yovanovitch will leave her post earlier than planned.

May 20, 2019 - Zelensky is sworn in as president. He orders a snap election for parliament.

July 21, 2019 - Zelensky's party wins a majority of seats in parliament during the snap election.

July 25, 2019 - Zelensky speaks with Trump Zelensky speaks with Trump via phone. Trump asks Zelensky to work with Giuliani and Attorney General Bill Barr on a Biden investigation, according to notes from the call released in the wake of a whistleblower complaint about the president's conduct. It is later reported that Trump told his acting chief of staff to block nearly $400 million in military aid to Ukraine before he spoke to Zelensky.

September 7, 2019 - Ukrainian and Russian media report that 70 individuals have been released in a long-awaited Ukrainian and Russian media report that 70 individuals have been released in a long-awaited prisoner exchange between Ukraine and Russia, a move that is meant to ease tensions between the two countries.

September 25, 2019 - Zelensky meets Trump on the sidelines of the UN General Assembly in New York. During a joint press conference, Zelensky says he does not want to become involved in American politics and he stresses that he did not feel pressured by Trump during the July phone call.

October 1, 2019 - Zelensky agrees to hold a local election in eastern Ukraine, signing accords with Russia, European monitors and separatists from the region. The agreement could pave the way for peace talks between Zelensky, Putin and European leaders. Ukrainian nationalists protest the agreement, describing it as a capitulation to Russia.