Google has paid tribute to London's Tube by replacing its logo with an homage to the famous Underground map.
The search giant made the switch to celebrate the Tube's 150th birthday.
It features the Google logo rendered in colourful Tube lines.
The famous diagrammatic Tube map was designed by Harry Beck in 1931, and eventually introduced as the official public map in 1933.
Beck was paid just ten guineas for his work, but he continued to design new editions until 1960.
However, it's not as well known that Beck's map was not the first to represent train networks in such a way.
A draughtsman working for the London and North Eastern Railway, George Dow, actually conceived the idea of a schematic map for network trains.
They were in common use on mainline rail maps, but not on the Tube until Harry Beck set pen to paper 82 years ago.