Heard an very unusual rumble of a low plane. Not unusual at all, with SEATAC, Tacoma Narrows airport the AFB and Army base near by. But this was odd. So I ran to the window. Say two V-22's flying side my side, so close it looked the bladed were gonna touch. They were under 1,000. So, without looking to much into it, I thought just the Marines used V-22's? Just thought it was weird. No Marine base in Washington State. There is a Navy base like 60 miles north west. But it's a Sub base.