Ick: A surfeit of kinship with the big 'mines' parachuted onto our area during NW Blitz...
Upside, if not contact-fused, but intended to lurk and complicate 'Civil Defence', they were too big to routinely misplace, usually got 'disposed' before their clocks ran down...
Down-side, the small and medium bombs had a remarkable ability to vanish under random rubble...
About two decades ago, the 'cable guys' back-hoe trenching soft verge near here got a 'clanger'. That ~100kg bomb had found the only muddy wallow / clay-delf in what had been a considerable expanse of shallow fields atop our infertile sandstone ridge, managed to bury itself for posterity.
Much 'sucking of teeth' and consultation of old maps: Ah, so its bomb-run had been this-away rather than that-away, and several long-fallow 'lots' suddenly became viable development propositions...