The Batcave is the secret headquarters of Batman, located in Gotham City.
While serving as a receptionist to the Teen Titans, Zan kept receiving phone calls asking for Batman. Upon correcting them to contact the Batcave, he revealed that he was not allowed to reveal its phone number. Beast Boy later answered another phone call directed toward the Batcave, claiming to be Batman himself.
Robin informed the other Titans that he would be visiting the Batcave, causing them to excitedly ask if they could accompany him. He denied them and traveled to Gotham City on his motorcycle where he was allowed entry after stating he was Boy Wonder. However, he left the door open unintentionally permitting the Titans to enter. He attempted to control his teammates as they played with Batman's equipment, and was force to tag along on a mission to battle the H.I.V.E. Five. After returning, the Batcave's artifacts were in ruins but Robin claimed he was no longer afraid of Batman. However, after a silhouette of Batman disproved that, he blamed the wreckage on the Joker and left frantically.
In order to get more signatures than the other Titans, Robin snuck into the Batcave and carefully approached Batman, who had fallen asleep in his chair, and puppetered his hand to sign his yearbook.
Batman has a shelf filled of souveniors. These include the bandages of Hush, Scarface, a Riddler plate, Jason Todd's (the second Robin) ashes, the crowbar Joker used to beat Jason Todd to death, Mr. Freeze's head, and Renuyu (the chemical substance which transformed Matt Hagen into Clayface, in Batman The Animated Series). He also has a bag of Kitty Litter, referencing Catwoman.