Officially known as Castillo San Felipe del Morro ( San Felipe Castle of Morro), El Morro is a military fortress which the Spanish conquistadors built and used nearly 400 years ago. The fortress was to be used yet again in World War II, this time by the US as a way to track German ships in the Caribbean Sea. Despite such dark history imbedded in the fortress, Puerto Ricans have found a distinctively brighter way to pass time with at El Morro; kite-flying. Across the green open space of El Morro, school kids and their parents gather certain times of the year to fly kites and have picnics. El Morro was determined a World Heritage Site by UNESCO back in 1983, and continues to recieve hundreds, thousands of visitors per year.