Google Doodle Celebrates 155th Anniversary of the Pony Express With a Game

— -- Giddy up!

Today's Google Doodle is celebrating the 155th anniversary of the first letter delivered by the Pony Express.

Embedded in the doodle is a game that gives the concept of the Pony Express a digital spin, allowing players to guide their galloping horses along a trail collecting letters while avoiding any collisions with cacti.

The Pony Express began on April 3, 1860 and created a system of communication allowing letter carriers on horseback to carry letters on routes stretching between California and Missouri by switching horses at various stations.

The mail delivery system carried tens of thousands of letters but was made obsolete by the invention of the telegraph 18 months later.