This California-based company runs more than 1,230 miles of U.S. rivers, plus many more in 14 foreign countries. And O.A.R.S. (Outdoor Adventure River Specialists) does a lot of good in those areas. Thirteen years ago, in the highlands of Fiji, O.A.R.S. worked with the local Mataqali people, a logging company, and a land trust to create the Upper Navua Conservation Area, which protects the region from logging and has raised more than $1 million for the community. O.A.R.S. offers a free guide school for the Mataqali, hiring the top performers. But the biggest reason clients keep returning is that O.A.R.S. produces unique, awe-inspiring trips, whether it’s craft-beer tasting on California’s Tuolomne River or floating past Bhutanese temples. Our recommendation: the 17-day epic on Bhutan’s Class IV-plus Drangme Chhu. $7,495.