A visitor enters through a doorway in the perimeter of the rim , walks through a passage .
A visitor climbs stairs to enter , then lies on the central plinth and looks upwards to experience the sky framed by the rim of the crater .
A visitor enters through a doorway in the perimeter of the rim , walks through a passage and climbs stairs to enter , then lies on the central plinth and looks upwards to experience the sky framed by the rim of the crater .