The Explorer Pass offers you free entrance to selected historic museums and sites. A 3 day or 7 day pass is available. The 3 day pass gives you 3 days of free entrance, that is valid for a 7 day period. The 7 day pass gives you 7 days of free entrance, valid for 14 days. Cadw is the Welsh Government's historic environment service working for an accessible and well-protected historic environment for Wales.