My worst crash was 2 years ago on a railway overpass; it's an old one, built in 1800s, with a cobbled carriageway, no bike lanes, so I usually take the paved sidewalk. It was early morning, the sidewalk was empty, so I got out of the saddle and powered up the incline, and was doing around 17-18 mph at the top where the sidewalk narrows down for whatever reason. I clipped the railing on the right side with my (flat) handlebars, which caused it to turn and the front wheel crashed hard into the railing. I went over the bars and crashed facefirst on the sidewalk. Lost consciousness for a second or two, came to senses bleeding profusely from my nose and face. A passer-by asked if I needed an ambulance; I was going to tell that probably not, but felt that my teeth are not quite where they used to be and the palate is moving around, so I just nodded, and was rushed to hospital. Aftermath: concussion, Le Forte type 2 fracture (broken nose, both eye sockets, upper jaw on both sides, effectively disconnecting the central part of the face from the rest of the skull), broken cheekbone, and a couple of wounds on my face. Had facial surgery and have now 3 titanium implants to hold it all in place.
The bike had a severely bent fork and pinch flats along destroyed tires - on BOTH wheels, which I still can't wrap my head around how I managed to pinch flat the rear tire as well.