Hmmm, obvious answers might be places like a government building, shopping mall, airport...but I'll go out on a limb and say maybe the first AED was installed at a school's athletic department? It is always so sad to hear about kids who drop dead after being hit in the chest with a line drive or who collapse from some undiagnosed heart condition.

Funny...nursing home never popped into my mind when I thought about this question. I wonder why. That also seems like an obvious first place to install these but it just didn't register in my brain until now.