The Panama Canal is a key transportation route between the Atlantic and Pacific Oceans. Without the canal, shipping and other vessels would either need to travel south around the tip of South America, or they would need to offload their goods to be transported across land to another vessel.
The Panama Canal consists of three sets of locks (Gatun Locks, Pedro Miguel Locks and Miraflores Locks), two artificial lakes (Lake Gatun and Lake Miraflores) and artificial channels. In addition, Lake Alajuela acts as a reservoir for the canal.
Entering from the Atlantic side of the canal, a ship arrives through the Caribbean Sea and then traverses the Gatun Locks. The Gatun Locks are a series of 3 locks, or steps, which lift a ship from the level of the Atlantic Ocean to the level of Lake Gatun.
The locks work by closing off the ship from the waterway behind it and then opening up the culverts beneath the locks connected to the waterway in front of the ship. Through gravity, the water levels will equalize and once equal, the gate in front of the ship will be opened for the ship to move forward and continue with the process.
Once the ship has traversed through Lake Gatun, it then proceeds through the Chagres river and then the Culebra Cut (or Gaillard Cut), going under the Centennial Bridge, until it reaches the Pedro Miguel Locks. Unlike the Gatun Locks, the Pedro Miguel Locks consist of only one step. Once past the Pedro Miguel Locks, the sip travels through Miraflores Lake and then through the Miraflores Locks, which consist of two steps. The ship then continues underneath the Bridge of the Americas and then out through the Gulf of Panama to the Pacific Ocean.
Mules (mulas) are train locomotives that help steer large ships through the Panama Canal to prevent a ship from hitting and damaging the canal. The mules run on rack tracks, train tracks with a toothed rail down the middle to help the train climb steep inclines. The rack tracks run along both sides of the Panama Canal. Large ships are steered by 4 mules on each side of the ship, two in the front (bow) and two in the rear (stern). The mules are for steering and don't actually tow the ships. Smaller vessels don't use the mules, but instead use hand lines which are controlled by the ship's crew.
The Panama Canal was built by the United States and completed in 1914. The Panama Canal stretches 48 miles from the Caribbean Sea to the Pacific Ocean and is a major shipping passageway.
In 1977, Jimmy Carter signed the Torrijos-Carter Treaties which declared that control of the Panama Canal would be turned over to Panama on December 31, 1999.
In October of 2006, Panama voters overwhelmingly approved a national referendum on a $5.25 billion expansion of the Panama Canal. The plan calls for the largest modernization plan in the 92-year history of the Panama Canal, which would allow the canal to handle modern container ships, cruise liners and tankers that are too large for its current 108-foot-wide locks. The plan is to build a third set of locks on the Pacific and Atlantic ends with a completion date of 2015.