Waterfront real estate. Most of the Annapurna Circuit is walking through, across or halfway up valleys. There are only a few places where you actually cross a mountain range, so most of the time you are following the millions of years old trails that the water cut long before humans ever arrived there. There are a few advantages to this, there is always a fresh breeze and sunshine on the river, even in the steepest valley, but most importantly, you constantly have access to water. In fact, the only days we had trouble keeping our bottles filled, were those were we crossed a ridge.