Template:Canals opened in YYYY category header/doc

 is used to create categories of the form "Canals opened in YYYY", where YYYY is a 4-digit year.

e.g.
 * Category:Canals opened in 1784 ✅

It is not for use on other types of categories, e.g.


 * Category:Canals opened in the 1840s ❌

The template creates navigation tables and puts the page into the correct parent categories

Usage
No parameters needed.