Great Gates and Admirable Arches

Monumental arches draw our admiration and awe while gateways sometimes open the passage to another world. Here's a mixed bag of natural and man-made arches and gates from all around the world that I have seen - sometimes in passing, sometimes making a special effort to see. Most have left an impression of one sort or another, be it consideration of the forces of wind and water that created the natural ones, the pride of powerful men who erected arches to mark their triumphs, the tide of history that has passed through them, the lives of the person they were named for or the genius that created them.