Blue Lagoon

The water here is shockingly blue - not the murky brown you'd expect from a former chalk quarry in rural Hertfordshire. Blue Lagoon, just outside Henlow, is exactly what it sounds like: a striking body of water that's become something of a pilgrimage spot for swimmers, photographers, and anyone after a bit of unusual scenery in the Home Counties.

It's a straightforward visit. You can swim if you're brave and the conditions allow it, though the water stays properly cold year-round. Most people come for the novelty of it all - the contrast between the electric blue water and the chalky banks creates decent photos. There's a walking loop around the perimeter if you fancy stretching your legs without getting wet.

Who benefits most? Outdoor types and swimmers, certainly. Families with young kids might find it less engaging unless your lot are into geology or splashing about. It's not a destination in itself, but it slots nicely into a wider exploration of the area. The nearby Ashridge Farm Caravan and Motorhome Club Campsite makes a logical base if you're spending a few days hereabouts.

Allow an hour, maybe ninety minutes if you're doing the full walk and taking photographs. Go in spring or early summer when the water colour is most vivid - by autumn it can look a bit tired. Winter visits are moody but cold, so pack accordingly. Admission appears to be free, though you should check locally before heading out.