This is one of the draws for the Paris-Roubaix spring classic race, a +200 mile, single day race with dozens of sections of rural cobble stones. Though, generally well maintained, the roads are narrow and brutal on modern road racing carbon-fiber bikes on 23mm wide tires. Lots of attrition from accidents. Typically pretty wet weather for the (spring) race and the cobbles are slippery and also get muddy. Riders tend to ride on the dirt shoulderer when they can, because it's smoother, but this can lead to tire punctures. The sections of cobbles are also narrow, so getting around 200 riders through is harrowing by itself. Smallest mistake by one rider compounds quickly.
Also mechanicals such as punctured tires and tossed chains are common. Rough corners/edges on the stones and gaps between cobbles easily puncture tires. The bikes have no suspension, so the chains bounce quite a bit, easily being tossed and in extreme cases, can be bent or broken if they jump a chain ring, requiring a replacement.
For their efforts, the trophy? A cobble stone with adornment.
The race is a spectacle. Probably one of the greatest one day spring classics of the UCSI Pro Tour. 6 hours or more of grueling, punishing cycling in crappy weather while being vibrated like crazy from the cobbles (the whole race isnt cobbles, but significant sections are, usually +20 sections, ranging in length of around a few kilometers each).