The Iditarod Trail Sled Dog Race covers over 1,600 km across Alaska from Anchorage to Nome.

The Sydney Harbour Bridge is one of the largest steel arch bridges.

The Gobi Desert is the fastest-expanding desert in the world and covers parts of northern China and southern Mongolia.

The Nile flows northward — it is one of the few major rivers in the world that flows from south to north.

The Channel Tunnel links the United Kingdom and France beneath the English Channel.

The Golden Gate Bridge spans the entrance to San Francisco Bay.

The longest river in the world is often considered to be the Nile.

The Sahara Desert has both sand dunes and rocky plateaus.

The Eiffel Tower was supposed to be demolished 20 years after its construction in 1889.