Complex sentence: The Pongo de Mainique is a 50 yard wide, two mile long "pongo" (canyon), said to be the most dangerous whitewater pass on the Urubamba River; however, many boats traverse it, depending on seasonal river conditions.
Split into simpler sentences: The Pongo de Mainique is a 50 yard wide, two mile long "pongo" (canyon). It is considered the most dangerous whitewater pass on the Urubamba River; however, many boats traverse it, depending on seasonal river conditions.