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

OK so the allied alone dropped 2,000,000 TONS with strategic bombing alone.

That does not count naval batteries, artillery, CAS support, Mines, etc.

You also have to account that not every bullet or bomb works 100% of the time.

A strong example of that is the battle of Somme in ww1. The britished shelled the Germans for 6 days straight. Literally 24/7 for 6 days and half of their shells didn’t even explode. They were duds.