The cave was discovered and used long before by Bruce Wayne's ancestors as a storehouse as well as a means of transporting escaped slaves during the Civil War era. The 18th century frontier hero Tomahawk once discovered a gargantuan bat (owned by Morgaine le Fey of Arthurian legend) inside what can be assumed will become the Batcave. Wayne himself rediscovered the caves as a boy when he fell through a dilapidated well on his estate, but he did not consider the cave as a potential base of operations until he rediscovered it yet again when he returned to Gotham to become Batman. In addition to a base the Batcave serves as a place of privacy and tranquility, much like Superman's Fortress of Solitude.
In earlier versions of the storyline, Bruce Wayne discovered the cave as an adult. In "The Origin of the Batcave" in Detective Comics #205 (March 1954), Batman tells Robin he had no idea the cave existed when he purchased the house they live in. He discovered the cave by accident when testing the floor of an old barn on the rear of the property, and the floor gave way. This story also established that a frontiersman named Jeremy Coe used the cave as a headquarters 300 years earlier. Bruce Wayne discovering the cave as an adult remained the case at least through Who's Who #2 in 1985.
Upon his initial foray into crime-fighting, Wayne used the caves as a sanctum and to store his then-minimal equipment. As time went on, Wayne found the place ideal to create a stronghold for his war against crime, and has incorporated a plethora of equipment as well as expanding the cave for specific uses.
The cave is accessible in several ways. It can be reached through a secret door in Wayne Manor itself, which is almost always depicted as in the main study, often behind a grandfather clock which unlocks the secret door when the hands are set to the time that Bruce Wayne's parents were murdered, 10:48 P.M. In the 1960s Batman TV show, the cave entrance has been shown to be behind a bookcase which was revealed when Bruce Wayne (actor Adam West) activated a red control switch hidden in a bust of William Shakespeare; when the secret switch is turned, the bookcase slides to one side, revealing the "Bat-Poles", which allow Bruce Wayne and his ward Dick Grayson (actor Burt Ward) to change into their Batman and Robin costumes en route as they slide down to the cave. An entrance under Bruce Wayne's chair in his office in Wayne Enterprises, as shown in Batman Forever, connects to a miles-long tunnel which Bruce travels through in a high-speed personal transportation capsule. In Batman Begins and The Dark Knight Rises, the cave is accessible through a secret door disguised as part of a large display case and is unlocked by pressing a sequence of keys on the nearby grand piano.
Another secret entrance, covered by a hologram, waterfall or a camouflaged door, allows access to a service road for the Batmobile. Another alternate entrance is the dry well where Bruce originally discovered the Batcave, highlighted especially during the Knightfall comic book storyline. At one point, Tim Drake and Dick Grayson use the dry well to get into the cave, which they had been locked out of by Jean Paul Valley during his time as Batman, and Bruce Wayne used it to infiltrate the cave and confront the insane Valley in the final battle between the two men for the title of the Batman. Lured into the narrow tunnel, Valley was forced to remove the massive Bat-armor he had developed, thus allowing Wayne, who was wearing his normal, slim Batsuit, to force him out of costume and renounce his claim to the title.
The location of the cave is known not only to Batman, but to several of his allies. In addition to the so-called "Batman Family", members of the Justice League and the original Outsiders are aware of the cave's location. Essentially, anyone who is aware of Batman's secret identity also knows the location of the Batcave, much like how people who have knowledge of Robin's identity have knowledge of Batman's; these, unfortunately, include such villains as Ra's al Ghul, who makes occasional visits to the Batcave to confront his long-time nemesis, and David Cain, who infiltrated the cave during the Bruce Wayne: Fugitive comic book storyline when he framed Bruce Wayne for murder.