Giant Water Lilies
These giant water lilies are so big, children used to be able to sit on them. But health and safety regulations say you're not allowed to do that any more.
The giant water lilies can be found at Kew Gardens, which is well worth a visit. The tropical greenhouses like this one are a real treat in cold grey London in the winter.

After visiting it's a pleasant summer day's walk, if you take it gently, along the river Thames to Animal Golf and Sky Pool.