Ramstein air show disaster
On 28 August 1988, three aircraft of the Italian Air Force display team collided during the Flugtag '88 airshow at USAF Ramstein Air Base near Kaiserslautern, West Germany. They crashed to the ground in front of a crowd of about 30,000 people, causing 70 fatalities (67 spectators and 3 pilots); 346 spectators sustained serious injuries in the resulting explosion and fire.
Source: Wikipedia — Ramstein air show disaster (CC BY-SA 4.0)