Greenwich Prime Meridian (park line)

The lowdown

The famous courtyard line at the Royal Observatory, where tourists queue to straddle zero degrees longitude, sits behind a paid barrier. But the Prime Meridian does not stop at the wall, it runs straight on through Greenwich Park, and a marker traces its line across the grass where you can stand with one foot in the eastern hemisphere and one in the western for nothing.

You miss the brass strip and the photo backdrop, but you get the same line, the same view down over the Old Royal Naval College and the river, and none of the entry fee. It is free, a little cheeky, and a perfect example of the everyday London magic this guide loves.