Termas geométricas, Thermal bath complex in Panguipulli, Chile.

Termas Geométricas is a thermal bath complex in the Los Ríos Region of Chile, near Coñaripe, on the southeastern slopes of Villarrica volcano. About sixty springs emerge at 80 °C and feed twenty pools set in a natural ravine, linked by 500 m of coihue-wood walkways painted intense red. The walkways form one continuous ramp without steps, with pools on both sides; eighteen pools are used for bathing at 35–45 °C, while the others regulate temperature through sluice gates.

The baths, formerly known as Termas de Cajón Negro, lie on the Fundo Cajón Negro owned by the Martini Becerra family, near Coñaripe beside the Aihué stream. The complex was designed by Chilean architect Germán del Sol, who also designed Termas Puritama in the Atacama Desert, and its construction was completed in 2004.

The red wooden walkways that link the pools were built to follow the natural shape of the gorge, stepping around trees and rocks rather than cutting through them. Walking from pool to pool feels like moving through the forest itself, not just passing between facilities.

The complex is reached by an unpaved road through the forest, which can be rough after rain, so a vehicle with some ground clearance helps. Once inside, the pools closest to the stream tend to be cooler, while those higher up on the rock face are usually the hottest.

Of the twenty pools, only eighteen are used for bathing, between 35 and 45 °C. The remaining two, at around 86 °C, are not for swimming: gates and locks let their water cool the rest, so the baths stay warm without any added heating.