San Diego has been a seaside escape for centuries. San Diego history dates back to the entrance of the Spanish into the United States in the 16th century. Spanish explorers founded its Presidio and the Mission San Diego de Alcala in 1769; subsequent settlers established a neighborhood in today's Old Town State Park. Downtown's streets were laid out in the mid-19th century; several early buildings from San Diego's history have been restored in the Gaslamp Quarter's historic district. Soon afterward, enterprising entrepreneurs commissioned the grand Hotel del Coronado, attracting vacationers to their evolving community. Others created amusement parks in Ocean Beach and Pacific Beach, further enticing visitors to call San Diego home. During San Diego's history, some of the most impressive Spanish-Colonial buildings were constructed in Balboa Park for the 1915-1916 Panama-California Exposition; its tiled California Tower has become a treasured landmark, and several of the expositions' ornate buildings house the park's museums. In 1935-1936, a second exposition brought further lasting developments to the park, making it San Diego's cultural hub. San Diego history, both of the past and modern day, has become strongly rooted in cultural diversity, colorful customs and meaningful traditions.