GMT Monument Orwell

A modest stone monument marking the Greenwich Meridian sits on farmland east of Royston, and if you're expecting Greenwich Observatory drama, you'll be disappointed. This is the real deal though - the actual zero longitude line that divides the world into eastern and western hemispheres, and it runs right through Cambridgeshire rather than just through London. The monument itself is fairly understated, which is oddly fitting for something so globally significant.

It's the kind of place that appeals to geography bores and anyone obsessed with maps. Kids will find the concept mind-bending for about five minutes, then want to leave. The walk to reach it across farmland from Royston is pleasant enough if conditions are dry, though you'll need proper directions - it's not signposted within an inch of its life like major attractions. Allow an hour including the walk and a quick look about.

Timing-wise, any hour of daylight works, and there's no charge. It pairs reasonably with a Cambridgeshire holiday from Shepreth Mill or Guilden Gate, both within easy driving distance. Highfield Farm and Cambridge Camping sites are also nearby if you're basing yourselves locally. The surrounding countryside is genuinely lovely - rolling fields and proper rural England - so don't visit just for the monument. Combine it with a walk to stretch the legs, grab lunch in Royston, and treat the monument as the quirky full stop to a proper day out.