Guests traverse sharp ridges, cross a suspension bridge of dizzying heights and scramble over the final summit, all the while taking in the snow-capped mountain scenery and watching the occasional eagle fly overhead.

BBC: North America by cable and bridge

At issue now is the Cross-State Air Pollution Rule that attempts to limit the levels of harmful emissions as they traverse across state lines.

FORBES: Winning the Presidency: Banking Clean Air or Bucking EPA?