@coodawoodashooda
Ill start.
- Buckingham Palace
- House of Commons
- Windsor Castle
- Hampton Court Palace
- Llangollan cannal
- Edinburgh castle
- Hadrian's wall
- Culloden battlefield
- Royal Mile
10. Cairngorms
All of these things will still be there when they are adults and they can go see and appreciate more - so I wouldn’t feel too ouch pressure to run around the country with a tick list to see monuments necessarily.
However as PP have said there is often a lot more on your doorstep and in the neighbouring counties that can be day trips and often as engaging. Local history stuff builds a sense of connection, belonging, identity and pride that can be taken into adult life. Local stuff is often cheaper and more accessible so you can do more of it more frequently rather than waiting for a once in childhood big holiday.
We tend to focus on museums, events etc in the winter (indoors) and then landscape (beaches, rivers, countryside - walks, wild swimming, picnics etc ie doing physical stuff doors in the summer.
I also think just wandering around a village, historic part of a small town and just observing, exploring and experiencing / absorbing its differences and energy etc easy. Which region of the country are you in as posters might be able to point you to hidden gems near by? We discovered loads of new experiences on our doorstep during lockdown.
As a destination thing we loved a boat trip out to see the seal colony with their newborns (hundreds up close) on the North Norfolk coast from Blakneys Point.