The Alter Elbtunnel (also called the Old Elbe Tunnel, St. Pauli Elbe Tunnel) is a pedestrian, bike and motorist tunnel (though cars are not permitted), which travels underneath the River Elbe. It connects central Hamburg to the southern side of the river. Opened in 1911, the tunnel was built to serve the port and shipyard workers as a connecting route between the Landungsbrücken and Steinwerder piers. It became a tourist attraction when the "new" Elbe tunnel opened in the 1970s. It has been undergoing renovation for the past several years.

While walking through the quarter-mile-long tunnel, take time to look at the tile reliefs that line the walls, which portray starfish, dolphins and other creatures. Past travelers enjoyed the experience of walking beneath the river and taking in the great view from the opposing side. Others said it provides an interesting photo opportunity, though there is little else to do.

It is free of charge for pedestrians and cyclists to use the tunnel 24 hours a day. You'll find the Old Elbe Tunnel off the Landungsbrücken U-Bahn stop. For more information, visit the port authority's website.