Cuevas del Drach, also known as the Caves of Drach, is a famous underground cave system located on the east coast of the Spanish island of Mallorca. These caves were first discovered in the 19th century and have since become a popular tourist destination.

The caves feature a series of large underground lakes, with one of them, called Lake Martel, being one of the largest underground lakes in the world. Visitors can take a guided tour of the caves to see the various limestone formations, including stalactites and stalagmites, that have been formed over thousands of years.

One of the most popular attractions in the caves is a classical music concert that takes place daily on a small boat in Lake Martel. The concert is a unique experience that takes advantage of the incredible acoustics of the cave system.

The caves are open to visitors year-round, with tours running several times per day. Visitors should wear comfortable shoes, as there are some uneven surfaces and stairs to climb. The temperature inside the caves is around 21 degrees Celsius (70 degrees Fahrenheit) year-round, so visitors should dress accordingly.