Abandoned railroad routes in North America
One thing that always catches my eye is seeing from satellite views the oddly shaped ghosts and footprints of long-gone railroad tracks and byways, which for decades after (if not a century), leave their mark on a city's streets and blocks.  And then happening to walk by it in person on the ground.   Like for example, <a href="https://www.google.com/maps/@37.7545858,-122.4138878,311m/data=!3m1!1e3" rel="nofollow">https://www.google.com/maps/@37.7545858,-122.4138878,311m/da...</a> , or <a href="https://www.google.com/maps/@37.404972,-122.137255,913m/data=!3m1!1e3" rel="nofollow">https://www.google.com/maps/@37.404972,-122.137255,913m/data...</a><p>You can see this in SF Mission and the old Southern Pacific lines, and why some blocks are so oddly shaped, and why there are parks that have the strangest configurations.  Out of place diagonal lots, parks, roads.   Very hard to erase those legacy shapes.<p>Similarly, seeing long stretches of green or empty space and realizing that there's a giant water pipe underneath stretching from the Sierras, and that's why there will never be a house built on that <xyz> lot.<p>(Funny, and I never seem to find among my friends anyone else who takes interest in it.)