Royal Palace of Madrid (Palacio Real)

This former home of the Spanish royalty is an opulent palace with nearly 3,000 rooms -- though only about 50 are on public tour. Many experts suggest definitely viewing the sumptuous Reception Room, the State Apartments, the Royal Armory and the Royal Pharmacy. They also say the Library and Painting Gallery are quite pleasing, as is the outdoor Patio de Armas.

The majority of visitors were wowed by the luxuriousness and the grandeur of the palace.  But many recent travelers also complain of the long lines to get in, though most of these also said the Royal Palace was worth the wait. Jump off the metro at either the Opera or Plaza de España stops.