For millennia, bridges have played a vital role in connecting cities - now even countries - over roads, water and railways. The earliest versions were often simply trees cut down and laid across gaps. Now, technology has improved at an incredible rate. 

But what is the oldest bridge in the world that is still standing? It is a corbel arch bridge, constructed during the Mycenaean Period, in the Bronze Age, some 3,354 years ago. Incredibly, it is still used by pedestrians, even cars, today.

The Arkadiko Bridge is located in the Peloponnese, Greece, near a modern road which connects the archaeological sites of Tiryns and Epidauros in Argolis. The bridge, which stands at 72 feet long and 18.4 feet wide, is thought to have been built around 1330 BC.

It formed part of a military highway between the two ancient cities, which formed part of a wider Hellenic road network. 

Its impressive layout and the alignment of the road indicate that horse-drawn chariots could use it. Over three thousand years later, locals continue to use it. 

The most interesting feature of the bridge is the way it was constructed. 

The bridge has remained standing, but does not use any form of binder, such as mortar. Instead, the weight and the symmetrical alignment of the limestone blocks, placed on the vertical axis, makes the bridge stable.

Some of the boulders have been shaped roughly with a hammer, while the majority remain unworked. Gaps between them have also occasionally been filled in with smaller chunks of limestone. 

Arkadiko Bridge is one of four known Mycenaean corbel arch bridges near Arkadiko, which are all of similar design and age.

One of them, Petrogephyri bridge, crosses the same stream 0.62 miles west of the Arkadiko bridge.