Every portal in Google Street View
Sometimes the metadata about where an image on Google Street View is gets messed up (usually happens with unofficial coverage), creating a portal. If you enter one end, you will be teleported to the other. They are one-way, with the red points being entrances and blue points being exits.
These are only the portals longer than 5000 kilometres - there are FAR more in reality.
Source: MapLibre API Data Viewer
u/Royal-Barracuda-314 — 3 days ago