Meta Tags are placed in website following the header. They are two types mainly "meta description tags" and "meta keyword tags". These tags can be seen by the spiders from search engines. They are necessary for spiders to have information regarding your website. These concept is very much used in SEO (Search Engine Optimization). Meta Tags are written in HTML codes.
If your website is about the "travel" you may add the meta tags like "places to visit", "most visited countries"...etc.