San Juan, Puerto Ricos capital and largest city, sits on the islands Atlantic coast. Its widest beach fronts the Isla Verde resort strip, known for its bars, nightclubs and casinos. Cobblestoned Old San Juan features colorful Spanish colonial buildings and 16th-century landmarks including El Morro and La Fortaleza, massive fortresses with sweeping ocean views, as well as the Paseo de la Princesa bayside promenade.