In pictures: Panama Canal undergoes maintenance

Workers from the Panama Canal Authority weld a gate at the bottom of the Miraflores floodgate during routine maintenance. The canal greatly reducing travel time between the Atlantic and the Pacific by eliminating the need for ships to go around the tip of South America. The construction claimed the lives of an estimated 30,000 workers, many from diseases like malaria and yellow fever. Arnulfo Franco / AP Photo

Panama Canal's workers inspect sewers in Miraflores locks western gate during maintenance works. Ed Grimaldo / AFP

Panama Canal employees clean sewers in the Miraflores locks western gate. Ed Grimaldo / AFP

A Panama Canal employee works in a dry chamber of the Miraflores locks. The overhaul and culvert maintenance of the locks will take seven days around the clock to complete. Carlos Jasso / Reuters

The Miraflores locks western gate during maintenance works. Ed Grimaldo / AFP

An empty boat is seen in a dry chamber of the Miraflores locks during its periodical maintenance at the Panama Canal. Carlos Jasso / Reuters

The Miraflores locks western gate during maintenance works. Ed Grimaldo / AFP

A group of men work on the maintenance of the dry chamber of the Miraflores lock at Panama Canal. Alejandro Bolivar / EPA

Workers from the Panama Canal Authority weld the bottom of the Miraflores floodgate during routine maintenance. Arnulfo Franco / AP Photo

The Miraflores locks western gate during maintenance works. Ed Grimaldo / AFP

A Panama Canal employee takes a break in a dry chamber of the Miraflores locks during its periodical maintenance. Carlos Jasso / Reuters

Once a year the Panama Canal closes some of its locks to traffic for maintenance works. The construction of the ship canal across the Isthmus of Panama a century ago transformed international trade.