Why isn't there a DNA archive for endangered species anywhere in the world?

Okay, so today I am at the zoo getting drunk and ogling animals, and after a long chat with one of the zookeepers, I am now forced to ask this question.

Like, climate collapse is a real thing that will render most species extinct, and most conservation efforts are focused on, well, conserving what we have. But I don't know of any effort to preserve samples of animal DNA, be it blood, gametes or whatever, so that if a species does go extinct, it could in the future, in principle, be revived.

So are there any zookeepers, biologists or other knowledgeable people in the house who could explain this? It seems like a serious overlooked gap in species preservation that needs to be closed sooner rather than later.