As allies around the world rallied to support Ukraine as it marked one year since the start of Russia’s invasion, a group of diplomats in London showed their support in an unusual way: swimming in a Hyde Park lake. 

Estonia’s Ambassador to the U.K. Viljar Lubi invited his colleagues and fellow countrymen to take a swim in Hyde Park’s Serpentine lake in central London on Friday to not only honor Ukraine’s perseverance in the face of Russia’s aggression, but also to celebrate Estonia’s Independence Day, which falls on the same day.

Dozens of people stripped down to their bathing suits first thing Friday morning as the temperature hit 37 degrees Fahrenheit.

“For centuries, Estonians believed that taking a dip in freezing water improved your health and also built resilience, so this is all about building resilience, which we all need,” Lubi said.

Ukraine’s own ambassador to the U.K. was there, cheering on the swimmers. But he politely declined to go for a dip. Vadym Prystaiko admitted to CBS News the tribute was “unusual,” but welcomed the display.

“People courageous enough to jump into the water [are] showing their support for the citizens of Ukraine who are now struggling with a very cold winter back home,” he told CBS News.

Prystaiko offered a message of hope for Ukrainians at home and abroad, saying he believed his country would survive Russia’s aggression.

“I know we will get through this war, and we will come to the reconstruction of Ukraine, which has been devastated by Russians,” he said. 

Later Friday morning, Prystaiko joined Britain’s Prime Minister Rishi Sunak at Downing Street to observe a solemn minute of silence, as Big Ben’s and Elizabeth Tower’s bells rung out to mark one year of war. 

Elsewhere, vigils and ceremonies were held worldwide in support of Ukraine. Even in Serbia, which maintains friendly relations with Russia, hundreds of protesters demonstrators turned up for a march against the war. 

In Germany, pro-Ukraine activists defiantly dumped a destroyed Russian T-72 tank in front of Berlin’s Russian Embassy.

One of the organizers of the stunt said the scrapped tank “stands as a symbol of the downfall,” and said Putin’s regime will collapse.