Avondale Cave is the cavern from which Avondale Spring surfaces in present-day Avondale Park.
Though the spring, then on the property of Peyton King, was already noted for the sweetness of its water, the opening into the cavern was first recorded as becoming accessible during the mid-1880s, with visitors describing a 20-foot-deep crystal clear underground channel. At that time, curiosity-seekers also reported finding arrowheads and carved-out niches as evidence of prehistoric human occupation. One entrepreneur secured permission from King to quarry brown marble from the cavern, with limited success.
At one point a load of dye was introduced to the underground stream and its stain became visible later in Valley Creek near Rickwood Field. Less reliable reports involved young explorers emerging from the cave after entering an iron-ore mine elsewhere, or entering the cave and emerging elsewhere in East Lake much later.
One fantastic story, printed in the Birmingham Age-Herald in 1886, told of a pair of explorers pilfering a boat from the lagoon and working it into the cave entrance where they attempted to row upstream to find the source of the underground river. Failing to do so, they drifted back downstream, missing the cave entrance, and proceeding to drift under the city of Birmingham, listening to the roar of furnaces and the rumble of trains. After passing the city, they spied a light high up in the darkness and, investigating, discovered a boat tied up at a small landing, from which a rickety stair ascended to a doorway carved into the rock. Through the door they could see a room where a young woman snoozed on a couch, a man engraved a metal block with a stylus, another man, an African American, worked a press, and a third man, who was outlaw Steve Renfro, presided over the counterfeiting operation. Not wishing for trouble, the explorers tiptoed back to their boat and returned to the current. After a restless nap, they awoke still in the cavern, but soon located a pinprick of light which eventually grew into an opening through which they emerged into the Warrior River. They continued as far as Tuscaloosa where they spent the night before taking a train back to Birmingham.
The entrance to the cave was sealed in the 1930s, but re-discovered later. A group of trained spelunkers mapped as much of the flooded cavern as they could in 1983, finding most of the passages disappearing quickly into mud-filled crevices.