The eyes that peeped out from the cracks of the shiny black police helmets looked sad. Ukrainian riot police, most of them men in their 20s, lined up under the arch of a building on Lutheran Street in Kiev on Monday night. In the snow and cold wind, hundreds of police troops had been waiting for their commanders’ signal to clear the crowds and barricades surrounding the presidential administration building, under siege now for days.

Metal barricades and buses covered in opposition stickers blocked the streets. Thousands of people wrapped in flags marched in the frosty, smoky air. The nearly three-week anti-government uprising had left its traces all around the Ukrainian capital. More pro-E.U. protesters with colorful flags arrived to take shifts around their “duty posts,” the barricades and small camps they built, facing walls of shielded policemen. Some activists were singing the national anthem around improvised open stoves. Others discussed the police attack earlier that night on the office of the INTV opposition channel and speculated about a possible crackdown by the Tiger battalion, famous for its violence.

“My son is your age. He speaks five languages and he studies engineering in Germany,” Victoria Yerosimenkova said quietly to one of the young policemen in the line. “I am sure you, too, would like to think of yourself as a European man.” Victoria and her husband, Alexander, were a well-traveled middle class couple with two children. For two weeks now, they had participated in the street protests. Alexander described their agenda: “We hope that President [Viktor] Yanukovych will stop asking Vladimir Putin what to do with Ukraine’s future. We want to become Europeans. This is our main goal.”

The atmosphere of Kiev’s “Eurolution” appeared peaceful and perfectly organized. On Monday, older activists immediately took two drunk young men in black masks away from the camps. Protesters rested and warmed up at a Lutheran church. A few men who felt sick came for a checkup with a volunteer cardiologist, Irina Gord. “I have treated 37 people today, aged from 18 to 70, mostly complaining of various colds or blood pressure,” she said. The doctor’s plan was to stay on duty through the night and help injured protesters, in case the planned crackdown took place.

It was not the first time hundreds of thousands of Ukrainians gathered in the streets of Kiev in the middle of winter. During the Orange Revolution, people camped on the central Independence Square for days, in spite of the bitter frost. But it was not the cold that people were worried about this time. “People realize that if we give up, hundreds will go to jail,” said Ilya Isupov, a modern artist. “What happened to the Moscow opposition activists, who are facing years of jail, could very well happen here. But Kiev will not allow that to happen.”

In the meantime, the brightly illuminated heart of “Eurolution,” Independence Square, lived its passionate night life. Loud Ukrainian music cheered a few thousand people who had camped out for the night. Opposition activists took turns speaking on stage. Everyone was polite and helpful, sharing food or a place to get warm in a tent. Several giant portraits of the opposition’s imprisoned leader, Yulia Tymoshenko, faced the crowds from the frame of what was supposed to have been a holiday tree. “Look, this is our square that changed us, made us better people,” said a young filmmaker, Yevgeny Gvozdei. “And this is the best Christmas tree in the world.”