London Aquariums

The tanks here are proper displays of what swims beneath the surface - freshwater species mostly, with enough going on to hold a child's attention for a solid couple of hours without them losing the plot. You'll see pike, perch, carp, and the usual suspects, all well-kept and visible enough that you're not squinting through murk trying to spot anything. It's the sort of place that works brilliantly if you're camping at Elstree Park or Home Farm Glamping and the weather's turned a bit dodgy.

Families with younger kids will get more mileage from it than teenagers, frankly. There's interaction potential - feeding times do draw a crowd - and the layout's straightforward enough that you won't need an hour just working out where you are. Allow 90 minutes to two hours; any longer and you'll have run out of fish to look at.

It sits just outside Elstree, which is useful because you're not hemmed in by London traffic getting there. If you're basing yourself at one of the local parks, this fills a gap nicely on a day when walking Aldenham Country Park feels like too much graft. Not a destination in its own right, but a decent wet-weather option that beats sitting in a caravan watching the rain. Free entry would make it a no-brainer; admission charges mean you'll want to check they're doing something worth your time before you pile in.