Throughout San Juan, there is evidence of the city’s Spanish influence. Centuries-old, two-story houses line the streets of the Old Town, many of them brightly hued with pastel facades. Some of the city’s most historic structures have been transformed into cultural venues. In the stately Ballajá Barracks, built to house troops in the mid-1800s, the Museum of the Americas chronicles the region’s heritage. The metallic-blue 16th-century La Fortaleza, once a defensive citadel, is the oldest continually used executive mansion in the Americas, today home to the city’s governor.