The United States’ southern border with Mexico is 1,933 miles long ... The Rio Grande and the rugged terrain around the river serve as a natural barrier. In between, there’s an assortment ...

The natural border is the river Bidassoa, which flows into an estuary dividing the two countries. As you go upstream from the river mouth, the view changes. Imposing and colourful Basque buildings ...

Arkansas’s northern boundary was shaped in 1813 when Arkansas County was formed within the Mississippi Territory. When ...

the natural border between Colombia and Panama. Leis arrived in Bajo Chiquito after a long canoe trip up the Turquesa River, where he met boats full of migrants who, after spending the night in ...

The world's largest enclosed body of water – the Caspian Sea – forms a natural border on Turkmenistan’s western side. This serene blue expanse, edged by the beautiful beaches of Turkmenbashi Bay and ...