As six robots battled it out on the floor of the DAR Constitution Hall’s auditorium during the FIRST Global Challenge competition Tuesday afternoon, a cheer rose above the din of voices echoing across the stands.

“Team Hope! Team Hope! Team Hope!”

The cheering came from a corner of the stadium where a group of boys from Team Lebanon — wearing rainbow clown wigs — stood next to Team Palestine. They, and teams from Libya and Jordan, were lending their voices to support a group of Syrian refugees, known as Team Hope. It was one of many times when teens would spontaneously break out into cheers for competitors.

When they weren’t cheering, hundreds of teens from 157 countries mingled, chatted and leaned in for selfies in the sweltering corridors of the concert hall at the first international Global Challenge competition. In between making final adjustments on their robots, a bonding experience that has become central to this competition, they signed each other’s T-shirts and exchanged pins. If they did not speak the same language, they all understood the thrill, the frustration and the anxiety that comes with competition.

These are precisely the kinds of friendships FIRST Global founder Dean Kamen, an inventor, hoped to build — ones that crossed languages, cultures and geopolitical frontiers. His lofty vision is one in which graduates of this program put aside politics to solve the world’s most pressing challenges, like shortages of clean water and the myriad problems wrought by global climate change. In this year’s competition, teams built robots to sort contaminated water from clean water — actually orange and blue plastic balls — to get them thinking about the real-life challenge that many face getting enough clean water.

“If we can get kids from around the world to deal with the same issues … we could compete on the same team,” Kamen said on Sunday evening, in remarks at the opening ceremony. “You don’t have to have self-inflicted wounds created by arbitrary differences and politics.”

This cauldron of competition — with countries sending some of their brightest and best aspiring engineers — forged plenty of unusual friendships. Team Armenia and Team Turkey, who come from countries whose relations are strained — were allied in one match. The Armenian team also helped Lesotho make modifications to their robot.

“You have to put politics aside,” said Lilit Tarumyan, a 16-year-old team member. Her teammate. Maria Ter-Minasyan, chimed in: “They were some cool guys!”

The contest is called a “coopera-tition,” with points given to teams for working together to form alliances.

Under their country’s flag, three young Iranian men tinkered with their robot on Tuesday afternoon, in preparation for the final, nerve-racking matches of the FIRST Global Robotics competition. Just feet away, Team Israel was busily making adjustments to theirs. The two countries have hostile relations. But in this corner of the DAR Constitution Hall, separated by no more than 30 feet, the teens from both countries forged an unlikely bond.

They chatted about robots and politics, and then the two teams huddled together for a group photo with founder Kamen. And then the teens wished each other good luck.

“Please, see us today, we Israelis and Iranians were together and happy,”said Mohammad Reza Karami, the mentor for Team Iran. “You also can see, learn and be together.”

The competition capped weeks of drama in which two teams — one from Gambia and Afghanistan’s all-girls squad — appeared to be in jeopardy of competing in the U.S. when their visas were initially denied. Their plight garnered international attention and sympathy. The Gambian team finally received their visas in early July, according to the Associated Press. But the Afghan girls did not get their visas until President Trump intervened at the last-minute, granting them passage to the U.S.

Alieu Bah, an 18-year-old Gambian team member from Serakunda, said the team was crestfallen when their visa applications were initially denied. But they did not give up and continued to put in hours of work — sometimes seven hours at a stretch — on their competition robot, with plans to ship it to Gambians living in the U.S., who would compete in their place.

“We worked hard. And even when we didn’t get it, we worked hard,” said Bah, who added that he was just excited to see Gambia represented in the international competition. But he was still thrilled when he heard the State Department had reversed its decisions. “I’m proud to be here.”

Tuesday, First Daughter Ivanka Trump came to the hall and met with five other all-girl squads, including the teams from Jordan, Brunei, Vanuatu and the U.S. She then pulled the lever to start a friendly match between the six teams.

Kawsar Roshan, a 15-year-old member of Team Afghanistan, said Trump was welcoming, telling her through a translator: “You’re most welcome. I’m happy you made it to the U.S.”