The Pony Express, the horseback mail service that helped connect the East and West coasts of the United States in 1860 and 1861, completed its first delivery exactly 155 years ago today.
To honor the occasion, Google put a nifty Doodle on its homepage -- an interactive game that has you picking up and delivering mail while fighting various obstacles, including bandits and avalanches, on your way.
The game is simple and pretty easy to finish, but collecting every single letter on your way is no easy task (I've managed to pick up 69 out of 100). Let us know if you've managed to do better in the comments.
Google commemorates famous events and people with its Doodles almost every day, but most of them are images; interactive Doodles and games are usually reserved for special occasions. In March, Google celebrated the 40th anniversary of the Rubik's Cube with an interactive cube, and the start of the World Cup in June 2014 was also marked with an animated Doodle.
Google also posted a short video history of the Pony Express, as well as a behind-the-scenes look at the new Doodle, in the video below.