A bridge.
People build bridges to cross deep rivers or valleys. Bridges are structures that span a gap or obstacle, providing a safe passage for people, vehicles, and goods to cross over. They are often constructed using a variety of materials such as concrete, steel, or wood, depending on the location and purpose of the bridge.
A bridge.
A bridge
people build briges
colordo
they have strong and long legs that help them cross deep rivers
Rivers' surface located in deep valleys can be below of the ocean surface. Furthermore, there are underground rivers which certainly are below sea level, depending on how deep such rivers are placed below-ground.
Normally flowing water, such as rivers will slowly cut through land to form valleys cliffs and trenches.
North Korea has rivers, active volcanoes, lakes, mountains, deep valleys and caves also.
The term used for narrow deep valleys is "ravine."
Those deep valleys are mainly in Wales, in the southwest of Britain.
Cro-Magnons