Lost River Caverns
 Lost River Caverns is a natural limestone cavern consisting of 5 chambers. The caverns were formed by the karstification or dissolving of the limestone by water. In the past the caverns have been called Rentzeimer's Cave and Lost Cave. The Lost River so named because the source and mouth of the river have not yet been discovered flows through it. The caverns are located on the east side of Hellertown Pennsylvania United States.