How are WW1 or WW2 era bombs still regularly found in gardens and houses around UK and Europe?

Question

The day after or week after these were dropped 60-100 years ago, did people not think, there’s a bomb over there we should make it safe.

Edit: I singled out the UK because they discovered a bomb from World War Two today in Plymouth. I know the UK is still in Europe.

In: Other

Answer 1

From what I read the kinetic energy of bombs lets them go deep underground and the soil above them collapses onto them. So if it does not explode it becomes buried. And there were a lot of bombs