Towering 'sponge' dome in Brazil is the secret source of nearby hot springs

In the Brazilian town of Caldas Novas, a massive, sponge-like dome known as the Caldas Novas dome or Serra de Caldas stands tall, rising up to 1,000 feet above the surrounding landscape. This 12-mile-long and 7-mile-wide structure, which is approximately 600 million years old, serves a crucial role in supplying the region's famous hot springs with warm water. The dome's dark, monolithic appearance and its role as a giant sponge filled by the Cerrado savanna biome contribute to its significance in the local ecosystem.