St. Augustine's historic district is the oldest continuously inhabited European-established settlement in the continental United States. Founded in 1565 by Spanish explorer Pedro Menéndez de Avilés, the area features cobblestone streets, colonial architecture, and significant landmarks like the Castillo de San Marcos, a 17th-century fortress. Visitors can explore various museums, shops, and restaurants that reflect the city's rich history. The district is home to notable sites such as the Lightner Museum and the Cathedral Basilica of St. Augustine, showcasing the blend of Spanish and American cultures that define this unique destination.