When I was in college, I got fucked in a botanical garden after hours by a security guard. Very atmospheric.
My ex also had me suck him off in the car on a long road trip, parked at in an empty church parking lot. He also tried to fuck me in a random shady bar bathroom in the French Quarter of New Orleans, but that felt a little too scary.
Not full sex, but I once got a partial BJ in the bathroom of a church from the weird girl from my school while her brother stood watch.
Nice brother