The word 'cordillera' means 'mountain chain' in Spanish. Colombia's three cordilleras were formed millions of years ago as huge plates of rock underground slowly collided and pushed the land upwards. Today those peaks are still covered in cloud forests, moorlands and snowfields - a completely different world from the tropical coast just a few hundred kilometres away.
Because Colombia's mountains are so close to the Equator, temperatures don't change much between summer and winter - instead, the temperature depends on how high up you go. Colombians talk about 'clima' (climate) in terms of altitude: warm and tropical near the valleys, cool and misty in the middle, cold and windy near the peaks. Farmers grow different crops at different heights.
The Andes in Colombia are full of ancient volcanoes, some still active. Hot springs bubble up where water seeps deep underground and is heated by rock. Communities living near volcanic soil have some of the most productive farmland anywhere - volcanic soil is incredibly rich in minerals.
At the very highest points of the Andes in Colombia, above about 3,000 metres, is a special kind of landscape called 'páramo' - a high-altitude moorland covered in strange spiky plants and often wrapped in mist. Páramos are incredibly important because they store water and feed the rivers that flow down to the cities below.