The Gaillard Cut, or Culebra Cut, is an artificial valley that cuts through the continental divide in Panama. The cut forms part of the Panama Canal, linking Gatun Lake, and thereby the Atlantic Ocean, to the Gulf of Panama and hence the Pacific Ocean. It is 12.6 km (7.8 mi) from the Pedro Miguel lock on the Pacific side to the Chagres River arm of Lake Gatun, with a water level 26 m (85 ft) above sea level. Construction of the cut was one of the great engineering feats of its time; the immense effort required to complete it was justified by the great significance of the canal to shipping, and in particular the strategic interests of the United States of America.
The United States took over on May 4, 1904. Under the leadership of John F. Stevens, and later George Washington Goethals, the American effort started work on a wider, but not as deep a cut, as part of a new plan for an elevated lock-based canal, with a bottom width of 91 metres (300 ft); this would require creation of a valley up to 540 metres (a third of a mile) wide at the top. A vast amount of new earthmoving equipment was imported, and a comprehensive system of railways was constructed for the removal of the immense amounts of earthen and rocky spoil.