Preventing cats from knocking over terrariums

[Johndeaux22]

I’m putting together a terrarium setup mostly for pleurothalids, along with some other low light/high humidity plants in a 55 gallon aquarium. My wife is concerned that one (or all?) of our 4 cats will knock it over. Does anyone have any ideas to prevent this from happening? I was thinking of fabricating a lip out of angle iron that the tank sets into on top of the stand I built, and anchoring the stand to the wall. Any other ideas would be greatly appreciated.