Hands of all ages grip the cold, silver metal bar. Pelados with piercings hang halfway out the door when it opens, somehow stepping back into the electric train just before the door closes.

Short, straight lines pan the full length of the metro, where a one dollar ticket will give you a free tour of the city, announcing in Spanish and English the nearby must-see locations at each stop. The city of three million people seems smaller because there’s little pollution and a fraction of the traffic in Bogotá, and thanks to the integrated metro system, you can get anywhere in the city in about half an hour with just one ticket.

From the metro, one can see some of the city’s oldest buildings and churches and everyday happenings. Women hang clothes up to dry and men brush their teeth on their apartment balcony. At night, the green Medellín mountainside turns dark, lit only by specks of soft golden lights.

The metro culture insists on order. Safety is a priority, and police officers make sure no one eats, drinks or sits on the ground in the metro system.

“Don’t cross the yellow line,” said the police officer to one Colombian woman.

Last summer Brittany Warrick taught English in Medellín and often opted for the metro since it was comfortable and safe. “It’s very clean, and you can’t get lost in the metro,” Warrick said. “And there are cops at every stop – the guys in green are everywhere.”

Weston Halter taught with Warrick and agrees the metro stays clean. He wishes it would run later at night, though, since it closes at 11 p.m. “I don’t know how many times I had to hail a taxi, and that’s dangerous downtown,” Halter said.

Perhaps the city’s greatest equalizer, its metro system serves all, bringing those who live far away by car to the center in a matter of minutes.

The Wall Street Journal and Citigroup named Medellín the world’s most innovative city of the year in 2012 for finding “solutions to classic problems of mobility and environmental sustainability.” But the metro is not perfect.

If it’s rush hour in the centrally located San Antonio station, the metro packs just as full as Bogotá’s TransMilenio. Suits and uniforms rustle past one another up three flights of stairs, 15 stairs each, running for an open green seat just to breathe a bit. It’s hard to move.

Arms, legs and bags push against your body, close but not quite comfortable, like the small, tin-roof houses on the city’s hills, especially those visible from the San Javier cable car.

Los desplazados call those small spaces home. Displaced from violence in other parts of Colombia, they’re like those that take the metro: different people, same place.

Kindergarten teacher Adiela Agudelo thinks that if Medellín can build something as great as the metro sys- tem, it can improve in other ways, too. While the city has a history of violence, homicide rates have dropped in the city that was home to the drug lord Pablo Escobar.

“If we want to have a good city, we can do it,” Agudelo said. “We did it with the metro, which is the other face that we can show the world.”