7 unreal rivers. Crystal pure, unbelievably stunning.

Londons Thames: Restored, vibrant, thriving again. Engineerings triumph!

Choleras grim 1800s legacy: The Great Stink.

Tara, Europe: Pristine. A glistening European gem.

Caragh River: Southwest Irelands emerald heart, nourishing rich farmlands. A European marvel.

Rhine: Europes second-longest, 1,230 km, powering its central and western heartland.

Hotel kettles boil away bugs for safety. Next: Manzanares River, South America calls!

St. Croix River: North Americas 164-mile lifeline, feeding the Mississippi.

This North American artery connects Wisconsin and Minnesota.

Torne River, Europe: The colossal heart of Norrbotten.

Torne River: The wild, shared artery of northern Sweden and Finland.

Hotel kettles: Clean brew or hidden risks? The surprising truth.