KIEV—A rueful smile played across Vitaly Klitschko’s lips as the former world heavyweight boxing champion spoke about the challenges he’s faced as the mayor of Ukraine’s capital city. Even after five years in office, he’s dealing with “corrupt and criminal” officials up and down the municipal government. There are days, he says, when he goes home, looks in the mirror and tells himself: “You don’t want this job.”

But after all he is Vitaly Klitschko, a 6’ 7” mass of brawn known as Dr. Ironfist who knocked out a stunning 87 percent of his opponents when he was in the ring and was never knocked down himself. He and his brother Wladimir, also a world champion heavyweight, totally dominated the sport for years. So Vitali goes to bed, wakes up in the morning and tells himself: “You won’t surrender.”

Mayor Klitschko, now 47, does not throw out remarks the way he once threw punches. He takes long pauses during our conversation, as if weighing his thoughts about a job he’s been in this long with, as he tells it, so many frustrations. His critics ask how he could hold power for five years and still claim to be fighting an uphill battle. They say at this point, whether he participates in it or not, he owns the corruption.

“I am two meters tall, I have 115 kilos of well-trained muscles in me and I am not even going to tell you about my staying power, you can watch my fights on video,” he says. “But I don’t have enough physical strength to break this system.

“Nothing can be done without a team of reliable people, professionals, who are ready to reform the rigid institutions,” he says, blaming a system of government nationally and locally that thwarts him. “The state machine is fighting back. It rejects changes.”

Klitschko is no coward, certainly, but when it comes to fighting crime and corruption, he suggests, not many around him show enough courage to make a difference. “People from my administration come to me complaining about somebody extorting money right here at the administration, so I say, great, let’s go and together catch these thugs, but the victim immediately backs up and says: ‘I am not taking part in your hunt.’”

Running the city can seem not only thankless, but dangerous, and there are constant threats to public order. Klitschko pulls out his cellphone and shows dozens of warning messages his administration has received over the previous two days: bombs allegedly being planted in schools, kindergartens, malls and restaurants. Some of these potential terror calls come from the war-torn east of the country. “It is our responsibility to check every site, make sure there is no bomb,” he says.

Yet despite the suffering of a nation afflicted with a Russian-backed insurgency, Klitschko’s Kiev is remarkably free and open. Among other things, he is very serious about allowing rallies in the capital. Liberals, far-right protesters, anyone at all can yell any anti-government slogans they want without fear of police clubs or detentions. Hundreds of far-right militia march in the city every year and nearly every week crowds of protesters join rallies for one cause or another in front of Kiev’s courts, ministries or the presidential administration buildings.

Just last month more than 3,000 people, including several dozen soldiers from Ukraine’s army, joined Kiev’s Pride Parade. Police detained a few far-right activists preparing provocations against the LGBT marchers, but the biggest Pride march in Ukraine’s history went off peacefully.

“ Kiev should be the heart of our democracy, a capital for free-minded, liberated people. ” — Vitali Klitschko

Kiev residents are lucky they can exercise their right to self-expression so freely. In Moscow, by contrast, brutal police grab demonstrators at every non-sanctioned rally.

Mayor Klitschko explains his position: “Kiev should be the heart of our democracy, a capital for free-minded, liberated people.”

Ukrainians won this freedom after a long and sometimes deadly struggle. In 2004 Kiev saw an uprising called the Orange Revolution after authorities had stolen the outcome of an election. In late 2013, violence by the authorities backfired after police beat up young Ukrainians who came out onto the streets demanding more integration into the European Union. The clashes started what became known as the Revolution of Dignity, which ended in the ouster of President Viktor Yanukovych in early 2014.

“We are a freedom-loving nation—when Ukrainians witness injustice, dishonesty, they hit the streets,” Klitschko said. Back then he was one of the revolutionary leaders protesting on Maidan Square in the center of Kiev, just a few steps away from city hall.

There is a story the mayor’s critics like to recall from those days. Shortly after the Revolution of Dignity, Klitschko and the oligarch Petro Poroshenko met with another of Ukraine’s influential tycoons, Dmytro Firtash, in Vienna. The exiled Firtash had made most of his money at RosUkrEnergo, a major Ukrainian gas company that is a subsidiary of Russia’s state-owned Gazprom.

After that meeting Firtash claimed he was the kingmaker propelling Poroshenko to power as president and Klitschko to his office as mayor. “It was as if he was the one who divided Ukraine like a pie,” Yulia Mostovaya, editor-in-chief of the country’s Mirror Weekly newspaper told The Daily Beast.

Before that controversial visit to Vienna, Klitschko had planned to run in the 2014 race for the presidency. After, he ran for mayor of Kiev instead, and the city’s population elected him with 56.7 percent of their votes.

In our conversation, Klitschko denied that Firtash had any influence on him, insisting that he had gone to Vienna on March 25, 2014, to celebrate his brother’s birthday and ran into Firtash by accident at the hotel. “I’ve never signed any agreements with the oligarchs,” Klitschko told The Daily Beast.

Poroshenko is now out as president after his dramatic defeat by a television comedian turned politician. Almost three-quarters of the electorate voted Volodymyr Zelensky.

Meanwhile, Firtash is expecting his extradition from Austria to the United States, where he is accused of bribery and forming an organized crime group. The Austrian Supreme Court ruled last month in favor of the U.S. extradition request.

“ I am concerned about pro-Russian powers raising their heads again. ” — Vitali Klitschko

So other political powers have fallen but the boxing champion is still working in his spacious office at city hall on Khreshchatyk Street in the heart of Kiev.

“For as long as Klitschko kept his distance from the [national] political game, his position stayed strong,” Mostovaya told The Daily Beast. “But that might change soon.”

Two years ago independent investigative journalists criticized Klitschko for taking a charter plane from Naples to Kiev with a businessman, Vadim Stolar, known as Kiev’s “éminence grise,” a man behind the men on Ukraine’s political thrones.

The National Anti-Corruption Bureau has investigated Klitschko but so far, nobody has managed to present any solid evidence of the mayor’s personal corruption.

Klitschko is also attacked for alleged shoddy workmanship on the eye-catching pedestrian bridge he and his brother opened a few weeks ago. The mayor’s critics accuse him of failing to prevent the “waste” of millions of dollars on an attraction for tourists and lovers when thousands of war veterans and poor people suffer without proper state support.

But Klitschko argues he’s fixed roads and the sewage system, reconstructed the city’s run-down wastewater plant, and attracted investors to the capital over the last five years despite the war against separatists in the east of the country that has claimed more than 13,000 lives and displaced 1.6 million people. Today many of those displaced are among 200,000 newly arrived residents of Kiev. Coping with their needs is one of the mayor’s duties. But they are far from the only people coming here.

Today Kiev feels liberal, peaceful and cool, and it has become a destination for many young Europeans. Hipster bars and coffee shops have sprung up everywhere. The elegant new bridge connecting Volodomyr Hill, which dominates the city, and Khreschatyk Park, high above the west bank of the Dnieper River, is already a favorite venue for selfies. Much of the span is made of glass, giving the impression (disconcerting to some) that one is walking on air. To reassure and amuse people, Klitschko posted a playful video on Twitter of him and his brother jumping up and down on it.

The winds of change are blowing in Ukraine and many hope the new president, Volodymyr Zelenskiy, will keep his promises and reform the oligarchic system that plagues the economy and the nation’s governance. But Russian aggression, covert and overt, always looms on the horizon, creating divisions, undermining the credibility of the state.

Klitschko pauses even longer than usual before speaking about his expectations: “A successful and free Ukraine seems to be the Kremlin’s biggest fear; I hope to see the oligarchs’ influence on politicians grow weaker—this is the key demand of all Ukrainians, we need to liberate politics from the big business sharks,” the mayor says. He is convinced, he says, that during the transition to this new president’s government many people will try to grab a share of power, or all of it. Or, as Klitschko put it, “many people will emerge willing to catch some fish in the dirty water.”

“I am concerned about pro-Russian powers raising their heads again,” says the mayor.

While he was boxing, Klitschko and his family spent a few happy years in Los Angeles, in the upscale neighborhood of Bel Air. He says he misses his life in California, his American friends, and hopes to take a month-long break back there some time in the future. “But right now I live under constant stress. One to two hours of sports a day is the only thing that helps me stay free of depression; without my daily training I wouldn’t be able to function,“ he says.

For all his fame and his considerable popularity as mayor, Klitschko has not been able to build an effective national political organization. His “Punch” party is not among the five top parties taking part in parliamentary elections. And yet, Klitschko is ambitious enough to think the prime minister’s position may lie in his future.

He is proud of Kiev’s public places, parks and roads that the city has been fixing up or creating from scratch. Looking good, feeling good, seems to be the motto of the boxer once known as Dr. Ironfist.

“Instead of just talking of future changes, I can demonstrate that I have managed to change things,” he said.