Are you the kind of person who likes to spend hours exploring #HistoricalMaps of your neighbourhood? This might be exactly the thing for you... https://bothness.github.io/ons-basemaps/
UK Historic Maps Explorer

If you're interested in a country other than the UK, here are some more historical map viewers:

Palestine https://palopenmaps.org/
Ireland http://geohive.ie/
USA https://ngmdb.usgs.gov/topoview/viewer/
Various countries/cities http://davidrumsey.georeferencer.com/compare
Trento (Italy) https://timetravelmaps.github.io/trento/
Geneva (Switz) https://www.ge200.ch/carto/

Palestine Open Map

Palestine Open Maps is a new platform for map-based exploration and immersive storytelling. This alpha version of the platform allows you to navigate historic maps and search for localities.

Vanhat painetut kartat

@bothness That’s the official repository but for browsing this is easier! Old Finnish maps: https://vanhatkartat.fi/#12.6/65.0088/25.46912
Vanhat kartat

Katso kuinka kotiseutusi on muuttunut aikojen saatossa! Vanhat kartat -palvelu sisältää yli 10 000 karttalehteä vuosilta 1870 - 1997.

Vanhat kartat - Suomi