I quite often do photo walks with a friend and I've been known to hike 8 miles around central London in one day just because I enjoy taking photos, but there are 3 experiences in particular that inspired me.  

Two of them were military based, while the third was at a remote Arizona canyon.

The first was a private one-on-one tour around the British Army Apache helicopters base at Wattisham.  If that wasn't already amazing enough, I was allowed to take my camera and take pictures in the hangers & also on the airstrip with Apaches landing & taking off just feet away from me.  

The second, also military themed, was when I was invited to a families only day at RAF Lyneham.  I was able to get up close and personal to loads of big British & American planes, but the best part of the day was when the friend who invited me suggested we sneak away to the end of the runway to watch the worlds only flying Vulcan bomber take off and land.

The first two days wouldn't have been possible without friends with access, and I was just lucky enough to have been in the right place at the right time...

The third day is one anyone can do.  Antelope Canyon is just outside of the town of Page in Arizona.  It's on Indian land, and the local Indians run tours to the canyon (several miles along a dusty dry river bed).  If you're in Arizona I highly recommend it, but get there early in the day to avoid fighting with the tourists...  It's quite a popular attraction now, which although good for the locals, it's not so good for photography.

Scroll down a bit to see a few photos from my days...