Impenetrable.

Ok. Wow. We just got back from Meteora, and it was IMPOSSIBLE. Tell me, how does a stone-brick building stay atop a rock for 8 centuries. I'm not sure about this, but from the 13th-14th centuries, Christian monks built fortresses atop rocks that jutted STRAIGHT UP forty-one hundred feet high! People lived up there for YEARS! They built them to escape invaders, who had different religions. They still exist today, and we visited them. People actually STAY in them. It reminded me of the special Star Wars episode, the one and a half hour one, where the Jedi and clones climb up a completely vertical rock face, to get the droids on top. The Sith had stolen Jaba The Hutt's son (or nephew?), and were hiding him up there. Of course, the Jedi made it up, but they sustained heavy losses because the droids could fire down on them while they climbed. However, back in the 14th century, there weren't any lightsabers, blasters, AT-ATs, hover vehicles, or blaster cannons! The Jedi had it easy. Also, the only way for the monks to get INTO their monasteries was for someone to hoist a bucket down, and then pull it back up, with someone INSIDE it! So, imagine being about eighty feet high, hanging in a bucket that was probably reed! Scary, eh? Now, imagine swinging from side to side, banging against the rock face, while your fellow monks hauled you up! Crazy! We climbed the opposing hill, so we had a clear view of the monastery. Then, I noticed a thin cable carrying a box, that snaked its way above our heads. It was the modern bucket. Cue the dramatic music. There were people in there, occasionally glancing down. This one went horizontally, so it wasn't the same, and it was solar powered. We hiked around for a bit longer, and then headed down the hill. We were so tired, we called a taxi and drove the rest of the way! You should totally do it, just bring a six-pack of water. Or, rent a motorcycle/scooter. The second option would probably be easier. 

Sullivan

P.S. Greece has been everything I expected it to be, only more!