Back in mid-2013, Gamer Grandpa slipped and broke his hip, and was send to the nearby rehab hospital. On one visit, we arrived just as he'd been taken to physical therapy, so I had a gap of two hours to fill. Looked online and saw that there were no geocaches hidden anywhere in the vicinity...there was a huge gap between the caches to the north, south, east and west. So I figured I'd fill in my "time gap" by filling in the "geocache gap".
Just outside the hospital property, I came across a bridge over a canal, and in the sidewalk of that bridge there was a crack between tiles, juuust wide enough to slip a thin container in. I'd never seen a hide like that before...so I just HAD to "fill in the gap" with a geocache!
Alas, on 7/7/24, I came to check on the cache and the "gap" in the sidewalk has been filled in with some type of rubbery material. The original container may still be in there...but it's definitely no longer accessible even if it it. So I've hidden a different container nearby, in the most thematically-relevant spot I could find. When retrieving, wait until all passing muggles have moved along so you don't compromise the hide.
Have fun, stay safe....and cache on!