The largest railway station in Amsterdam is one of the gates to the city. It was opened in 1889 and the crowds of onlookers were so curious that they did not mind being charged money for the chance of looking at the building (only during the first days after its opening). Today, the entrance is free of charge but the place is still very busy because it is the focal point of Amsterdam's transport.
All public transport is centred around the Centraal Station, so you can get there (or from there) by various means of transport (trams, buses, metro). Inside, the station is clean and full of little shops where you can get what you need for your journey (snacks, newspapers, books etc.).
If you want to avoid the daily to and from rushing crowds of commuters, look at the main building just from the outside. Its most imposing feature for the tourists is definitely the exterior beauty of the building (and not so much its interiors).
