The Gotham Natural History Museum is a large museum located in Gotham City.
When the city fell after the events of "Devil's Snare", Doctor Trap looted a bunch of villains' lairs and collected various object which he all displayed in the museum. To keep people from stealing his loot, he filled the museum with dangerous traps. In "Catwoman" after finding out he had Firefly's flamethrower which they needed to break into Mister Freeze's lair, Harley Quinn and Poison Ivy decided to break into the museum. With the help of Catwoman they managed to avoid the traps and get out with the flamethrower.
At some point, the museum was reclaimed by the city and hosted normal museum objects again, including a pre-historic mosquito conserved in sap which Ivy needed for her "Edin serum". In "There's No Ivy in Team", Ivy led Harley, Clayface and King Shark on a heist to the museum to steal the mosquito. The plan began to go south, however, when a guard who wasn't supposed to be there spotted them. When the guard began opening fire against them, Ivy told the gang to run whilst she used her powers to get up to and in a vent leading to the right exhibit. She broke the glass and stole the mosquito before grabbing the rest of the crew and carrying them through the gun fire with her vines, using them to pull down several dinosaur bones on top of the guards to slow them down as they made their escape.