The U.S. supported the building of the Panama Canal to expedite (make faster) travel between the Atlantic and Pacific Oceans.

Factors such as tropical climate, mosquito borne diseases like malaria and yellow fever, difficult terrain and tropical vegetation affected the building of the canal.  There was also an increase in technology for engineering. 

The 48-mile international waterway allows ships to pass between the Atlantic and Pacific Ocean, saving about 8,000 miles from a trip around the southern tip of South America (Cape Horn).