Known as "The Pearl of the South," Ponce is Puerto Rico's second largest city. Because much of the city's colonial architecture has been preserved, Ponce has been declared a national treasure. Established in the late 1600s, Ponce is filled with museums, plazas, churches, fountains and homes from the colonial era. In the city center is the Plaza Las Delicias, a hilly neighborhood beloved by the people of Ponce. (ALAMY)