Coal Duty Obelisk

You'll find this rather austere stone obelisk standing in Greenwich, a 40-foot monument that most Londoners walk straight past without a second glance. Put up in 1699, it marked the boundary of the old Coal Duty boundary - a tax on coal coming into London that helped rebuild the city after the Great Fire. Not exactly a crowd-puller, but if you're into the sort of London history that doesn't get splashed across postcards, it's worth tracking down.

The obelisk itself is modest. No grand inscriptions, no theatrical stonework. Just a reminder that money and administration shaped this city as much as its grand buildings did. You can see it for yourself in minutes - there's no visitor centre, no ticketing, nothing like that. It's simply there, doing its job of marking a line in the sand that mattered once upon a time.

History buffs will find it interesting mainly as a footnote - evidence of how the early modern city actually worked. Kids won't find it thrilling, to be honest. But if you're staying at Abbey Wood Experience Freedom Glamping and fancy a walk around Greenwich's riverside, you can slot it into a bigger afternoon without any bother. It works better as part of a broader Greenwich wander than as a destination in itself. Free to visit, naturally. Allow five minutes maximum unless you're really keen on 17th-century tax collection.