Complex sentence: Shipping may be for commerce, recreation, or for military purposes; while extensive inland shipping is less critical today, the major waterways of the world, including many canals are still very important and are integral parts of worldwide economies.
Split into simpler sentences: Shipping may be for commerce, recreation, or for military purposes. While extensive inland shipping is less critical today the major waterways of the world including many canals are still very important and are integral parts of worldwide economies.