From Spiegel:

A team of archaeologists, scientists and software programmers has created a 3D virtual model of the city of Cologne as it was 2,000 years ago. Though not yet online, the software allows visitors to fly through the city in its Roman glory.

A new computer program will allow the curious to see Cologne, Germany's fourth-largest city, as it was almost 2,000 years ago, when it was a major northern outpost of the Roman Empire.

"Now, for the first time, people will be able to visualize what an amazing city Cologne already was in antiquity," said Hansgerd Hellenkemper, the director of the city's Romano-Germanic Museum.

The city's history stretches back to 38 B.C. After Julius Caesar pushed the empire north during his conquest of Gaul in the mid-first century B.C., the Romans resettled the Germanic Ubii tribe on the banks of the Rhine River. In 50 A.D., the settlement was granted the status of an official Roman city and was given the name Colonia Claudia Ara Agrippinensium. The city grew to be a major trading center, a status it still preserves today.

The program allows visitors to use a computer mouse to navigate a virtual "flight" around the city, where they will find impressive sights, such as the massive city wall and its monumental gates, the forum, the over 40-meter-high (130-foot) Capitoline Temple, the forum with its semicircular portico and the proconsul's palace.

The project, which has taken over three years to put together, is a collaboration between archaeologists, researchers and software experts drawn from the Archaeology Institute at the University of Cologne, the Köln International School of Design (KISD), the Cologne University of Applied Sciences, the University of Potsdam's Hasso Plattner Institute (HPI) and Cologne's Romano-Germanic Museum.

According to the project's Web site, the purpose of creating the model was to "allow Roman Cologne to be visualized using the findings of current research and to thereby make it comprehensible in its historical dimension to an even larger public."

While the model's content was completed this week and can be accessed using CAD software, it has yet to be made accessible online. The project's leaders have declined to specify when this process will be completed, but the project's team has already begun working on its next project, a virtual model of modern Cologne, dominated by the 157-meter (515-foot) twin spires of its famous cathedral.

Hamburg and Berlinalready have 3D city models that allow users to take virtual flights through the cities using Google Earth. Virtual models of other historical places also exist -- for example, for Rome, Pompeii and Herculaneum -- but in a different form. "Those were more like computer-generated animations rather than large-scale models that you could navigate," says Jürgen Döllner, a professor of computer graphics at the HPI, who led the technical implementation of the project.

Spiegel has some photos from the project too ... the project website has some info (in German) too ...