Parade organizers hailed this year's march as "the biggest and most colorful Pride in London yet."

The heart of the UK capital was decorated with rainbow flags and colorful balloons, as around 25,000 revelers on Saturday marched down Oxford Street and Regent Street, London's most popular shopping areas. Hundreds of thousands more were expected to continue partying into the early hours of the night in London's Soho district.

Read more: Soho's gay history revealed in new tours

By sunset, the UK Parliament's Palace of Westminster will also be illuminated with a rainbow flag for the very first time to commemorate the 50th anniversary of the UK Sexual Offences Act, which decriminalized homosexuality.

"Here in London you are free to be who you want to be and love who you want to love," London Mayor Sadiq Khan wrote on Twitter.

"Pride brings people together in joyful celebration of our values of freedom, tolerance and equality," UK Prime Minister Theresa May said in a statement. "It is a vivid display of the diversity which makes London one of the greatest cities in the world."

Organizers and revelers celebrate to honor of those who can't

Pride organizers said they wanted the city's 45th annual parade to send "a global message of hope, acceptance, activism and love ... and a show of solidarity to LGBT-plus people living in Northern Ireland, which has yet to legalize same-sex marriage."

British Olympic diver Tom Daley, who married his long-term boyfriend earlier this year, was among the high-profile names taking part at this year's march. "It's really important that we remember why Pride started - it's not just to have fun; it's about making sure that we make political progress, and making sure that we try and get equal rights for every single person across the whole world," he told the Agence France-Presse news agency.

Read more: Istanbul police fire rubber bullets, tear gas to keep gay pride marchers off the street

While celebrating the occasion, Norman Fowler, speaker of the upper House of Lords, also offered a somber note, pointing out that "homosexuality is still illegal in over 70 countries around the world." He added, "None of this will be solved by a march, or a display of lights in Westminster, but these acts will demonstrate to those who are being persecuted or abused that they are supported."

From Cologne to Colombia: A world of LGBTQ+ pride Christopher Street Day in Cologne In Germany, pride parades usually take place in major cities on weekends from June to August. Cologne held its 25th Christopher Street Day ceremonies - annually the biggest in Germany - on the first weekend of July. Berlin will celebrate on July 23, and Hamburg has scheduled a week of pride from July 30 to August 7.

From Cologne to Colombia: A world of LGBTQ+ pride Stonewall was a riot A police raid on the Stonewall Inn, a gay bar on New York's Christopher Street, on June 28, 1969, is a major milestone for the queer liberation movement. Some of the biggest US pride parades are held on the last weekend in June to commemorate the riots that followed the raid. After a gunman killed 49 LGBTQ+ people at a bar in Orlando this June, mourners paid tribute at the Stonewall Inn.

From Cologne to Colombia: A world of LGBTQ+ pride Dyke March Lesbian activists have established their own event for more visibility: the Dyke March. The first major US Dyke March took place in Washington, DC, in 1993 and drew 20,000 women. Bisexual and transgender women also join the processions. Organizers of the annual Dyke March in New York stress on their website that the event is "a protest march, not a parade."

From Cologne to Colombia: A world of LGBTQ+ pride Police assault on Istanbul Pride In 2016, the Istanbul administration prohibited any demonstrations during the city's annual pride observances. When protesters marched in a rally for transgender rights anyway, they were violently attacked by police. The officers used tear gas and water cannons to disperse the Trans Pride crowds. At the Istanbul Pride closing rally, police arrested several participants as well.

From Cologne to Colombia: A world of LGBTQ+ pride Bike Pride In Vietnam's major cities, cycling is one of the most common forms of transportation. That's why it makes sense that the first Viet Pride, in 2012, saw more than 200 participants cycling through the streets of Hanoi, Vietnam's capital. This year's celebrations will be held August 19-21. The events now draw close to 1,000 people.

From Cologne to Colombia: A world of LGBTQ+ pride Premiere in Johannesburg The first pride parade on the African continent was held in Johannesburg, South Africa, in October 1990. It was organized by anti-Apartheid activists. For the event's 20th anniversary party in 2010 (pictured), 18,000 people celebrated. Today, parade participants also protest against hate crimes such as the so-called corrective rapes of lesbians in townships.

From Cologne to Colombia: A world of LGBTQ+ pride Small steps in Uganda Homosexuality is a punishable offense in Uganda - but activists still organized a pride rally in the capital, Kampala, in August 2012. Two years later, Uganda's Supreme Court annulled legislation allowing for life imprisonment for "aggravated homosexuality" and banning the "promotion of homosexuality."

From Cologne to Colombia: A world of LGBTQ+ pride Out and proud in Colombia Colombia hosted its 2016 Orgullo (pride) celebrations on the first weekend in July. The country decriminalized homosexual activity in 1980. Today, same-sex couples can adopt children and enjoy the same pension and property rights as heterosexual couples.

From Cologne to Colombia: A world of LGBTQ+ pride Baltic pride Bad weather can't stop members of the LGBTQ+ community in Riga from celebrating. During the first pride parade in the Latvian capital, in 2005, protesters threw rotten eggs and bottles at the small crowd of 40 people who marched the streets. Today, Latvia takes turns with Lithuania and Estonia in hosting the annual Baltic Pride parade.

From Cologne to Colombia: A world of LGBTQ+ pride Century of sadness in Russia The last Moscow Pride (pictured) was held in 2011. The next year, the municipal administration banned pride parades for 100 years. Russian officials have repeatedly attempted to repress LGBTQ+ people. In 2013, the country passed a law criminalizing the distribution of materials to minors in support of "nontraditional" sexual relationships, which has led to a surge of homophobic propaganda. Author: Carla Bleiker



Homosexuality in the UK: 50 years legal

The British Parliament approved the Sexual Offences Act on July 27, 1967, which decriminalized homosexual acts in private between two men aged at least 21.

Legislation to allow same-sex marriage in England and Wales was passed by the UK Parliament in July 2013. It came into force on March 13, 2014, with the first same-sex marriages taking place on March 29, 2014. In Scotland, legislation was passed by the regional parliament in Edinburgh in February 2014. The law came into effect on December 16 that year, with the first same-sex marriage ceremonies taking place that very day.

By comparison, Germany legalized gay marriage just last week, making it one of the last western European countries to pass such legislation.

Watch video 01:31 Gay Pride parades: A tale of two cities

dm/jlw (AFP, dpa)