Researchers from Denmark and Barcelona have discovered an extra 100,000 kilometers.

Using the oldest satellite surveys, topographical maps and software, they have revealed the Empire was the size of the European Union and it had nearly 300,000 kilometers of roads - enough to stretch around the world more than seven times.

Many have become hidden over time, covered by new construction or disused.

But the researchers says the network of Roman roads gives us an understanding of how the empire shaped several continents.

The study, just published in journal Scientific Data, says the Romans operated an integrated transport system on a continental scale.

At the height of the Roman Empire in the 2nd century CE its population was a massive 55 million people.

The roads not only helped the Romans to continue their domination over distant lands, it allowed great quantities of trade to flow across the empire, especially the vast quantities of food needed to sustain the populations.

Lead author Tom Brughmans, an archaeologist and associate professor at Aarhus University in Denmark, says the movement not just of goods, but of people shaped the continent in a way which still affects us today.

He hopes scientists will find the study and his interactive map useful to understand more about the populations and how they existed at the time.

But he hopes it will also spark interest in anyone curious about the history of the Romans and the massive empire which dominated the continent.

The new high-resolution digital dataset and map, called Itiner-e, covers roads throughout the Roman Empire around the year 150 CE.