English: Western Kentucky's Mammoth Cave is the longest cave system on Earth, with 426 miles known and mapped as of March 2024. The name does not refer to the early discovery of fossil mastodon or mammoth bones here. Rather, the name refers to the immense size of many rooms and passages.

Seen here is a limestone cave wall at Violet City. This is at the southeastern terminus of Main Cave, the principal trunk passage in the Mammoth Cave Ridge part of the system. Main Cave has become erosively separated from the upstream continuations of the passage. The latter can be observed in Sandstone Avenue and Kentucky Avenue/Grand Avenue during the "Grand Avenue Tour".

Violet City can be observed during the "Violet City Tour", which starts at the cave's Historic Entrance and exits here at Violet City. The exit emerges from a sinkhole near the Carmichael Entrance. Violet City itself is a large breakdown pile that blocks Main Cave. Several sites in Main Cave have place names that include the term "City" (another example is Chief City). Such sites are large to enormous breakdown piles that led early tourists to imagine the remains of devastated cities.

The bedrock in Mammoth Cave consists of three Late to Middle Mississippian-aged units (from top to bottom): Girkin Limestone, Ste. Genevieve Limestone, and St. Louis Limestone.

Locality: Violet City area, southeastern end of Main Cave, Mammoth Cave Ridge, western Kentucky, USA