Peter Harrison Planetarium

The Peter Harrison Planetarium sits inside the Royal Observatory at Greenwich, and it's genuinely brilliant if you've never been inside one before. The dome theatre shows immersive shows about space - proper cinematic stuff with a screen that wraps around you. You're looking at the night sky projected overhead, learning about constellations and the cosmos without leaving London.

It's ideal for families with kids aged seven upwards, though adults often find themselves just as absorbed. History enthusiasts appreciate the setting within the Observatory itself, where you can wander the grounds, cross the Prime Meridian line, and get your head around how navigation worked before GPS. Allow two to three hours total if you're combining the planetarium show with exploring the rest of the site.

Admission is free, though the shows inside the dome do cost extra - usually around £9 for adults. Book ahead online; the shows fill up quickly, especially at weekends. Greenwich can get rammed with tourists, so go on a weekday morning if you can manage it.

If you're staying at Abbey Wood Experience Freedom Glamping just five miles away, this makes an excellent half-day outing. The site itself is worth an afternoon - the views across London from the Observatory are decent on a clear day, and the surrounding Greenwich Park is lovely for a proper walk afterwards. Not essential to your holiday, but solid value if you've got the time.