A Bering Strait crossing is a hypothetical bridge or tunnel spanning the Bering Strait between Cape Dezhnev, Chukotka, Russia, and Cape Prince of Wales, Alaska, United States. The bridge or tunnel would provide an overland connection linking Asia, Africa and Europe with North America and South America. The Bering Strait could be spanned by a series of three bridges via the Diomede Islands for a total distance of about 80 km (58 miles). The two long bridges would each be slightly longer in length than the Hangzhou Bay Bridge, currently the longest sea-crossing bridge in the world. The construction of such a bridge or tunnel would face unprecedented engineering, political, and financial challenges.
There have been several proposals made by various persons, TV-channels, magazines etc. The names used for such bridges have included The Intercontinental Peace Bridge and Eurasia-America Transport Link.. Tunnel names have included TKM-World Link and AmerAsian Peace Tunnel. In April 2007, Russian government officials told the press that the Russian government will back a $65 billion plan by a consortium of companies to build a Bering Strait tunnel.
The concept of an overland connection crossing the Bering Strait goes back before the 20th century. William Gilpin, first governor of the Colorado Territory, envisioned a vast "Cosmopolitan Railway" in 1890 linking the entire world via a series of railways. Two years later, Joseph Strauss, who went on to design over 400 bridges, including the Golden Gate Bridge, put forward the first proposal for a Bering Strait railroad bridge in his senior thesis. The project was presented to the government of the Russian Empire, but it was rejected.
Tsar Nicholas II approved a planned tunnel in 1905. Its cost was estimated at $65,000,000,  and $300M including all the railroads. These hopes were dashed with the outbreak of World War I and the Russian Revolution.
Interest was renewed during World War II with the completion of the Alaska Highway linking the remote territory of Alaska with Canada and the Continental United States. The Foreign Policy Association envisioned the highway continuing to link with Nome near the Bering Strait, linked by motorway to the rail-head at Irkutsk, using an alternative sea and air ferry service across the Bering Strait.
In 1958 engineer T. Y. Lin suggested the construction of a bridge across the Bering strait "to foster commerce and understanding between the people of the United States and the Soviet Union". Ten years later he organized the Inter-Continental Peace Bridge Inc, a non-profit institution organized to further this proposal. At that time he made a feasibility study of a Bering Strait bridge and estimated the cost for the bridge to be $1 billion for the 50 mile span. In 1994 he updated the cost to more than $4 billion. Like Gilpin, Lin envisioned the project as a symbol of international cooperation and unity, and dubbed the project the Intercontinental Peace Bridge.
In September 2005 when launching the Universal Peace Federation, Dr. Sun Myung Moon brought new light to the idea of building what he calls the "Bering Strait Peace King bridge and tunnel", calling all the world's governments to make a joint effort to realize world peace. On February 10, 2009, Sun Myung Moon's "Foundation for Peace and Unification" announced a competition for the design of a bridge across the Strait via the Diomede Islands. The winner (announced June 11, 2009), was a project entitled "Diomede Archipelago". It proposes a series of artificial islands that form two archipelagos extending the two continents, and three tunnels connecting the two Diomede islands and the archipelagos.
The depth of the waters themselves offer little challenge, as the strait runs no deeper than 180 feet. The tides and currents in the area are not severe. However, the route would lie just south of the Arctic Circle, subject to long, dark winters and extreme weather (average winter lows −20 °C with possible lows approaching −50 °C), and so building activity is restricted to five months out of the year. The weather also poses challenges to exposed steel. In Lin's design, concrete covers all structures, both to simplify maintenance and to offer additional stiffening. Also, while there are no icebergs in the Bering strait, ice floes up to 6 feet thick are in constant motion during certain seasons, which would produce forces up to 5000 tons or more on a pier.
An issue which is minor compared to financing and construction issues, is technical standards. Russia uses a different rail gauge and has other differences in technical standards compared to the USA. It can be solved in a similar way as it is solved at other borders, reloading (suitable for e.g. containers), bogie exchange or variable axles.
The area is also a very active seismic zone, posing additional technical challenges for either an undersea or bridge construction.
Aside from the obvious technical challenges of building a 80 km long bridge or a tunnel across the strait, another major challenge is that, as of 2010, there's nothing on either side of the Bering Strait to connect the bridge to. The Russian side, in particular, is severely lacking in infrastructure, without any paved highways or railroads for over 3200 km (2000 miles) in any direction from the strait. On the American side, one would need to construct at least 800 km (500 miles) of highways or railways in order to connect to the American transport network.
In 1994, Lin estimated the cost of a bridge to be "a few billion" dollars. The roads and railways on each side were estimated to cost $50 billion. Lin contrasted this cost to petroleum resources "worth trillions". Discovery Channel's Extreme Engineering estimates the cost of a highway, double track rail and pipelines, at $105 billion, five times the cost of the Channel Tunnel. This excludes the cost of new roads and railways to reach the bridge. The Discovery Channel proposal contains several extremely long suspension spans. The Russian government has proposed the project to link the Trans-Siberian Railway portion of the Eurasian Land Bridge to the rail network of North America. On the American side, a project to connect Nome (just 100 miles from the strait) to the rest of the continent by a paved highway is currently in the planning stage. The project has been estimated to cost $2.3 to $2.7 billion, or approximately $5 million per mile. 
The TKM-World Link is a planned link between Siberia and Alaska providing oil, natural gas, and electricity to the United States and Canada from Russia. The plan includes provisions to build a 64 mile (103 km) road and rail tunnel under the Bering Strait which, if completed, would become the longest tunnel in the world. As of 2007, the 53.85 km Seikan Tunnel is the longest tunnel of this type. The tunnel would be part of a railway joining Yakutsk, the capital of the Russian Yakutia republic, with the western coast of Alaska.
Russian Prime Minister Vladimir Putin, approved a plan to build a railroad to the Bering Strait area, as a part of the development plan for the years until 2030. The funding is however doubted. The 64-mile (103 km) tunnel would run under the Bering Strait between Chukotka, in the Russian far east, and Alaska. A cost estimate was US$66 billion. The plan involves creating a 6,000 km (3,700 mi) route through Siberia to facilitate economic ties to the US. A pipeline would be created to transport natural gas and oil from Siberia.