A Bering Strait crossing is a hypothetical bridge or tunnel spanning the relatively narrow and shallow Bering Strait between the Chukotka Peninsula in Russia and the Seward Peninsula in Alaska. In principle, the bridge or tunnel would provide an overland connection linking Asia with North America, although there is little infrastructure in the nearby parts of ASince the two Diomede Islands are between the peninsulas, the Bering Strait could be spanned by three bridges. Two long bridges, each almost 40-km long, would connect the mainland on each side to one island, and a third much shorter one between the two islands, giving a total distance of about 80 km (50 miles). The two long bridges would each be longer than the 35-km Hangzhou Ba 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 challengelaska and Russia.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 ft (55 m). 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 (−4 °F) with possible lows approaching −50 °C (−58 °F)), 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.