Map of the Schengen Area.
Light blue - Schengen Area
Dark blue - Countries with open borders (Monaco, San Marino, Vatican City).
Green - Legally bound to join the Schengen Area
Schengen_Agreement_map.svg.  This is a fork of the original image which wrongly shows/showed Ireland as having implemented Schengen.
Schengen_Agreement_map.svg: Ssolbergj
derivative work: Blue-Haired Lawyer (talk)