I find geology interesting, especially how slowly the earth (has) changed. Hence the many time-lapse videos, even though they can only cover much shorter periods of time. The stone in the photo is debris from a tunnel construction and contains so many fossilised ammonites. These lived 240 million years ago (Triassic – shell limestone) in a shallow sea and some of them were so covered by carbonate mud after their death that they were preserved. Over the millions of years, many more layers were deposited above it, which also petrified, the entire land has risen and partially lowered again, a lot of material has been removed again and now we walk around on these ancient testimonies of life.