I was working in the shed one day and heard a helicopter in the distance. Not unusual as Arch medical flies over multiple times a day, and we occasionally see Blackhawks. It kept getting louder and louder, and when the ground started to shake i decided to go out and see what the hell was going on. I stepped out to experience (and I choose that word carefully) a flight of 2 ch47s fly i maybe 100agl directly over my house. It was a borderline religious experience. The rotor wash, the SOUND, the smell of turbine exhaust. Awesome.