Serpentine Gallery

The Serpentine Gallery sits bang in the middle of Hyde Park, which means you can wander straight in from a stroll around the Serpentine lake without any faffing about with postcodes or transport. It's a proper gallery - contemporary art, usually rotating exhibitions that actually make you think rather than nod politely and move on. The building itself is nothing fancy, but that's rather the point. You get actual artists in here, not the safe corporate stuff.

Really it's for people who care about what's being shown rather than just ticking off a gallery visit. If you're dragging reluctant teenagers around, they'll get bored after twenty minutes. But if you're into current art practice or fancy something free to do on a drizzly afternoon in London, it's worth the detour from your picnic spot by the lake.

The beauty is you don't need to plan it. Pop in when you fancy, have a look at whatever's on, then head back outside to the park proper. No entrance fee, no booking required. Summer's the obvious time if you're staying at one of the nearby parks like Lovat Parks, but honestly the gallery works year-round - especially when the weather's rubbish and you want to be indoors for an hour.

Don't expect it to be the highlight of your trip. But as part of a park day in London? It slots in perfectly.