The Prometheus Caves, about 20 km north of Kutaisi near the town of Tskaltubo, are the largest known cave system in Georgia and one of the more spectacular in the Caucasus. The active cave extends for several kilometres; the section open to visitors is about 1.4 km long, illuminated throughout, and takes around 90 minutes to walk.
The cave system features stalactites, stalagmites, cave pearls, and underground waterfalls, with chambers of varying sizes and colours created by different mineral deposits. The most memorable section is an underground river, which visitors can traverse by boat as part of the tour — an unusual way to end a cave visit. The lighting is theatrical by design, which some find excessive, but the formations themselves are genuinely remarkable.
Most visitors reach the caves by taxi from Kutaisi or as part of an organised tour. The nearby Tskaltubo spa town, a faded Soviet-era resort built around natural mineral springs, is worth a brief look if you have time.