Gruta do Carvão, located on the island of São Miguel in the Azores, is a unique and stunning natural wonder that is not to be missed. This incredible underground lava cave system is a popular tourist destination, drawing in visitors from all over the world to explore its fascinating geological formations and rich history.

The Gruta do Carvão, which means "coal cave" in Portuguese, was formed over 800 years ago during a volcanic eruption. The cave was discovered in 1893 by a group of explorers, who were amazed by the sheer size and beauty of the underground space. Today, the cave is a protected natural monument, with guided tours available for visitors to explore its depths.

The cave is made up of a series of interconnected tunnels and chambers, which are illuminated by soft lighting to showcase the cave's unique features. Visitors can marvel at the impressive stalactites and stalagmites, which have formed over centuries as mineral-rich water drips from the cave's ceiling and floor. The walls of the cave are also covered in intricate patterns of lava flow, creating a stunning and surreal landscape that feels almost otherworldly.

The Gruta do Carvão is not just a geological wonder, but also has an important cultural and historical significance. During World War II, the cave was used as a shelter for local residents, who hid inside to escape the bombings that were taking place on the island. The cave also played a role in the island's coal mining industry, with coal deposits discovered in the cave in the early 20th century. Today, visitors can see remnants of the mining operations, including rusted machinery and rail tracks that were used to transport the coal.

The guided tours of the Gruta do Carvão take approximately 45 minutes, and are available in multiple languages, including English. The tour is suitable for all ages, although visitors should be prepared for some steep inclines and uneven terrain. The cave is open year-round, although visitors should check ahead for any closures or restrictions due to weather conditions.

In addition to the cave itself, the Gruta do Carvão also features a visitor center, which offers information about the cave's history and geology, as well as a gift shop where visitors can purchase souvenirs and mementos of their visit. The visitor center also includes a small cafe, where visitors can grab a snack or drink before or after their tour.

Overall, the Gruta do Carvão is an unforgettable experience that is not to be missed when visiting São Miguel. Whether you are a nature lover, history buff, or simply looking for a unique and exciting adventure, this incredible cave system is sure to leave you in awe.