HMS M.33

A real submarine sits on the foreshore at Lee-on-the-Solent, and you can actually walk inside it. HMS M.33 is a monitor ship from the First World War - low-slung, bristling with weaponry, the sort of vessel that looks equally at home in a museum or a battlefield. The metal hull is weathered but intact, and stepping through the hatches gives you an immediate sense of how cramped naval life was.

What strikes you most is the sheer engineering. Gun turrets, torpedo tubes, the tight quarters where crews lived for weeks on end. You're not just looking at it behind glass - you're ducking through corridors, peering into the engine room, understanding how these things actually worked. History buffs will lose an hour easily here; families with children around ten upwards tend to get genuinely engaged rather than restless.

It's free to visit and sits right at the water's edge, so allow a solid ninety minutes if you want to explore properly. The setting matters too - Lee-on-the-Solent is a proper seaside town with a shingle beach and promenade, so you can make a proper morning of it. If you're staying at Hayling Island Holiday Park a few miles east, this is an easy detour that breaks up a beach day without feeling like a museum visit.

Go when the tide's out if possible - you get better views of the hull, and the whole ship feels less hemmed in. Bring decent shoes; the metal walkways can be slippery when wet.