Amsterdam is capital of The Netherlands and world-famous for a) the Canals b) the Museums and c) the Coffee Shops and similar business. The International atmosphere makes it unique place in the world. A must-do is a boat tour through the canals with 17th century houses and house boats as well as a stroll through the red-light district.
Rotterdam is Europe's largest harbour and the 2nd largest city of The Netherlands. It is also known for modern architecture like the cube-houses and new market hall.
The windmills of Kinderdijk (near the city of Alblasserdam) are world-famous. Standing in the middle you may count 20 or so and - though no more needed to save the Netherlands - all still functional!
Maastricht is one of the oldest cities in the Netherlands. It is a cozy place where it is best to see the sites and enjoy a beer at the Vrijthof (main square) afterwards. Or have a coffee with "Rijstevlaai" (traditional cake). Once a year Andre Rieu gives a concert here, since this is his home town...
The Hague is home of the Dutch Government, but not the nation´s capital... The royal family lives nearby as do many other ´rich and famous´. Do visit the center with the old government buildings (Binnenhuis"), the Palace of Justice and the beach of Scheveningen where you should eat ´raw hering´.
Just North of Amsterdam is this community of two former fishermen villages. Volendam is best known for traditional farmer's clothing ('dracht') and eel. Edam, part of the same community, is world-famous for... cheese! Also nearby: Marken!
Alkmaar is known for the old and cozy city center. But it's cheese market (Friday Morning) is unique, probably in the world.