The Mersey Gateway Bridge Project includes the design, construction, financing, operation and maintenance of a 2,2 km reinforced concrete cable stayed bridge and access viaducts, and 9,3 km of motorways, including several junctions. The bridge is located between Runcorn and Widnes, in the Halton Borough Council, 13 miles away from Liverpool, in the Northwest of England, in the United Kingdom. FCC Construcción, Kier Construction and Samsung C&T are the three members of the Joint Venture in charge of the construction of the Main Crossing and the Landsides. The design is carried out by a joint venture constituted by Flint and Neill, FHECOR, URS and Eptisa. The budget for the construction is 454 million pounds. The construction period is 42 months from financial close. This essay tries to explain the reasons behind the construction of this major bridge and the main features of the construction process, highlighting the main challenges which must be sorted out, over the design and construction period. [ABSTRACT FROM AUTHOR]