On April 25, 1898, the United States declared war on Spain, heralding the beginning of the Spanish-American War. Fort De Soto, on Mullet Key, was commissioned to help defend the sea approach to Tampa Bay, Florida. The fort's main defensive feature was a grouping of eight 12-inch-bore mortars, each capable of dropping a half-ton projectile on enemy ships miles away; four of these historic mortars are still in place. In 1948, the fort's 884 acres were sold to Pinellas County, which had long coveted the land for a park. On May 11, 1963, the celebration for the grand opening of Fort De Soto Park featured appearances from Henry Fonda, Guy Lombardo, and Miss Florida. Thousands showed up for the opening ceremonies and were excited to explore everything the new park had to offer. These days, well over two and a half million people visit the park each year to enjoy its top-rated beaches and outdoor activities.