There is a lot of art around the centre of Medellín however the one thing that is striking, once it is pointed out to you, is the absolute lack of graffiti on the metro stations. In a city of more than 3 million people this is incredibly unique. As it was explained to us the Metro was and is viewed as a great victory for the people of Medellín and continues to be appreciated. I can attest to the fact that the trains we took were very clean and the system relativity easy to use. It is only metro train system in Colombia.