Crossing the river in Tibet was done in 1992 be a Yak hide boat serving as a ferry. The feet got wet, but the other side was reached safely. Tibet was in those days one of the greatest adventure destinations on the planet with so many unknown Elements, like no fuel available, landslides, flat tires and so many other obstacles on the way. But to me Tibet is till date one of the finest places to go to, as the nature is simply stunning and pristine. The high altitude might give some short breath and at times a headache, but this is offset easily by the most beautiful landscape one can dream off. So if you have not been, then go there!