Growing up in California I was used to wooden shingles. There's been a lot of code changes and you don't see as many since they're a fire hazard. But these medevial slate shingles in Beynac, France, were way ahead of us Californians. No way these will burn. Around since at least the 1300s, they've managed to pass the test of time.
"Rooftops of Beynac" © Kathy Dunham 2010