The Andes run all the way down the western side of South America - from Venezuela in the north through Colombia, Ecuador, Peru, Bolivia, Chile and Argentina. That is 7,000 kilometres - longer than the distance from London to Beijing.
Aconcagua's name probably comes from words in the Quechua language meaning 'stone watchman' - the mountain that watches over everything around it. From the top, you can see hundreds of kilometres in every direction on a clear day.
Even though Aconcagua is one of the tallest mountains in the world, you don't need special climbing ropes to walk to the top - just lots of warm clothes, lots of fitness and lots of patience. It usually takes climbers two to three weeks to walk up and back down, because they have to let their bodies get used to the thin air slowly.
Higher up, the air has less oxygen, so even taking ten steps can feel as tiring as running a sprint. People who climb high mountains say the most important skill isn't being strong - it's being patient.