Tourists photograph buildings you walk past every day. Familiar isn’t the same as seen.

Knowing where something is and having looked at it are different achievements. After a few hundred passes, your mind swaps the building for a label and stops rendering the thing itself, which is why you could not describe the front of your own school if somebody asked. The tourist has no label, so they have to use their eyes.

Choose one building you pass daily and give it two minutes. Stand still, look at the top, the doorway, the date if there is one, the bits that have been repaired. You will probably see three things you have never seen, in a place you would say you knew well.