There are a number of public holidays in the Netherlands. On these days shops, museums and attractions often close earlier, while schools, city councils, post offices and banks remain closed the whole day. King's Day, which occurs on 27 April, is a big celebration in Amsterdam and other parts of the Netherlands. Sinterklaas on 5 December is also a popular holiday that many people celebrate at home.
A list of public holidays can be found via the link below.