Canal

Canals are man-made waterways, usually connecting existing lakes, rivers, or oceans. They are used for transportation, often by barges or narrowboats on smaller canals, and by ships on ship canals that connect to the ocean. Inland canals preceded the development of railroads during the Industrial Revolution; some canals were later drained and used as railroad right-of-way.

Some rivers have also been 'canalised' to make them navigable.

Irrigation canals are man-made waterways for the delivery of water and preceded the use of transportation canals.

Canals have found another use in the 21st century, as wayleaves for fibre optic telecommunications networks.

Miscellaneous

Canal in the centre of
Amsterdam, The Netherlands

For a time until the early 20th century, it was believed that there were canals on Mars.