These two castles, both elements of the fortifications encircling the city, stand on either side of La Caleta beach. The fortress of Santa Catalina, entered directly from the promenade, was constructed in the 17th century. Its small chapel and a central patio planted with palms give it the sun-baked look of a Mexican mission. The castillo is now a cultural center where open-air concerts are held in summer. San Sebastián, meanwhile, is an imposing fort built (in 1706) on a small island connected to the mainland by a long stone causeway. This malecón is popular among locals and visitors as a pleasant place to walk for a cool breeze.