Gruta de las Maravillas (Cave of Wonders)

Under the city of Aracena lies a complex of caves, carved over millions of years by the forces of nature. Formations resembling chandeliers and curtains adorn the walls of the enormous galleries. Since the earliest documentation of the Gruta de las Maravillas in the 19th century, 2,130 meters (6,988 feet) of this cave system have been mapped, and about 1,400 meters (4,593 feet) of the cave are open to the public.

The waterways throughout the Gruta de las Maravillas are a dazzling turquoise color because of the minerals present. A cavern called the Salón del Gran Lago (Hall of the Great Lake) contains a massive subterranean lake.

Inside the cave, the temperature stays relatively constant throughout the year, ranging between 16 and 19 degrees Celsius (60-66 Fahrenheit), though the air is extremely humid.