Mariana, Minas Gerais, Brazil

Mina da Passagem

The world's largest gold mine open to visitors, active from 1719 to 1954 in Mariana, Minas Gerais, with approximately 30 km of tunnels. After decommissioning, abandoned galleries flooded with groundwater, forming a crystal-clear underground mineral-water lake at a constant 21 degrees Celsius. An altitude dive (~800 m), exclusively operated by Divegold since 1999; recreational section down to 21 m, with the lake extending to 240 m depth (record reached: 74 m). At around 20 m, divers can see antique mining artifacts: pickaxes, ore carts, and dynamite crates. Access via a trolley that descends 315 m into the mine shaft.