Hatfield Aerodrome Trail

The Hatfield Aerodrome Trail takes you round what was once a serious aircraft manufacturing hub - this is where they built the Comet, Britain's first jet airliner, back in the 1950s. Walking the perimeter, you get a feel for the scale of the operation: vast hangars, some still standing, cracked runways stretching into the distance, and the odd bit of industrial heritage dotted about. It's more atmospheric ruin than polished museum, which honestly works in its favour.

You'll need a decent pair of boots and a good hour to do it properly, longer if you stop to read the information boards and absorb the history. Aviation enthusiasts will find it genuinely moving - there's real substance here about British engineering and the golden age of commercial flight. History buffs will appreciate the industrial archaeology angle. Kids might get restless unless they're properly into planes; it's not a theme park.

The trail is free to access, which is just as well because there's no visitor centre or facilities to speak of. St Albans is just down the road, so you can combine it with a proper town day if you're based at one of the nearby parks like Cherry Green Trees or Commons Wood. The location works well as a half-day activity during a caravan holiday in Hertfordshire - enough to break up the week without demanding a full schedule commitment. Go midweek if you can; weekends bring the casual walkers who don't really know what they're looking at.