Wilanów Palace is one of the most famous and visited in Warsaw.It was built in mid 17th century by order of the king as his summer residence. It's barroque style and can be tour-visited in groups of 35 persons. The most memorable is it's gallery where you can see oaintings of Poland's most famous kings. If unwilling to pay, you can walk it's surrounding green area free of charge. It's open from 9am to 4pm in winter and 'till sunset in summer.