The Spanish Landing Park in San Diego, California commemorates the 1769 arrival of Spanish explorers, but offers lots of activities.
Today, there is a playground, sandy swimming beach, a boat launch, and a bike path. With a picnic area overlooking the harbor, pack a lunch and plan to stay all day. Gator by the Bay is held there with cajun food and music, and a mardi gras style parade.
If you bring the kids, make it a learning experience by examining the plaque commemorating the arrival of the Spanish, an event that shaped the development of San Diego and the new world.