A palatial structure built in 1533, this is the oldest executive mansion in the Western Hemisphere. La Fortaleza is surrounded by luxuriant gardens and overlooks San Juan Bay. Guided tours of the gardens are available Monday-Friday 9 am-3 pm. Reservations recommended. US$3 adults. 52 Calle Fortaleza, Old San Juan, San Juan. Phone 787-721-7000, ext. 2211. http://www.fortaleza.gobierno.pr.