I worked briefly as a mechanic for Boeing on C-17's. One incident (I did not witness but was told) was a C-17 somewhere in the middle east landed on a clear patch of dirt/sand, except right when they touched down they noticed a small concrete barrier in the middle of the field...
The nose gear went right into it. It was narrow enough to miss the rear tires. But the impact of the nose gear ripped it complete off the plane and left a gaping hole where once the fuselage touched, blasted a ton of sand straight into the interior of the plane. I think a specialty crew eventually made it out there and rigged a nose gear together good enough for a take off and landing where it then flew back to a Boeing facility near Lackland Air Force Base (I believe).