The Trans-Siberian Railway is a network of railways connecting Moscow with the Russian Far East and the Sea of Japan. Spanning over 9,000 kilometers, it is the longest railway line in the world and is considered one of the greatest engineering feats of the 20th century.
From Wikipedia
The Trans-Siberian Railway, historically known as the Great Siberian Route and often shortened to Transsib, is a large railway system that connects European Russia to the Russian Far East. Spanning a length of over 9,289 kilometers, it is the longest railway line in the world. It runs from the city of Moscow in the west to the city of Vladivostok in the east.