Wow - that hits pretty close to home. I spent the better part of my High School/College/and post-college days working for a large auto museum in Wisconsin. It was owned by a father and son, and between the two of them they had over 400 cars - all of them Indy Pace Cars, rare Muscle Cars, antiques; just about anything you can imagine.
They called me about 5 years ago with bad news - the main "barn" (a 200'x200' metal over metal shed) had burned to the ground. In it were most of the good cars - the 1970 GTO Judge convertibles, the 1970 Superbirds, the 1968 Shelby GT500KR Convertibles, the 1971 Buick GS 455-Stage 1, the 1970 Buick GSX, about 10 Corvettes, all 1963 - 1967 big blocks, etc...
I thought my heart stopped when I heard the news. Apparently, a painter (they did their own restorations in the shop next door) was working late one night and he was going to lay down primer on a 1950 Mercury pace car. It was cold in the shop, so he fired up the furnace to super heat the paint area. He forgot he left the furnace on and started spraying primer...about 3-4 sprays into it, the shed exploded (he was burned but lived, later committed suicide), and the fire spread quickly. Within 2 hours more than 150 cars were nothing but shells of their old selves.
I had a lot of great memories of those cars. We drove them a lot (parades, for fun, out on the town, etc), and now they're gone.
Worst part is: the painter committed suicide about 3 months later and the insurance only covered $250,000 of the $5M+ loss... They gave "book" value on the cars, as the father/son didn't have supplemental insurance.
Hindsight is always 20/20 - as towgt states, a sprinkler would have helped prevent some damage, and better insurance would have lessened the loss of the cars.
