Why Using This?
Canonical URLs solves the content duplication (multiple urls representing the same post/page) problem. Using canonical urls prevents search engines lowering your site’s ranking due to content duplication.
How it works?
It’s simply an HTML
<link> tag at the
<head> section with attribute points to the right or “canonical” url.
<link rel="canonical" href="http://example.com/taiwan-bike-routes-map">
Usually one uses a SEO plugin to generate this tag automatically.