The Egnatia highway project, which was constructed on the threshold of the 21st century, is one of the largest road construction projects ever constructed in Europe. It is the modern reincarnation of the great Roman highway known as the Via Egnatia. The 670 km Egnatia Motorway, which is part of the Trans-European road network, is a modern closed dual carriageway motorway spanning Northern Greece from its western to its eastern border. Egnatia highway traverses extremely diverse natural morphology of great beauty. It crosses the Pindos mountains, which are the southernmost extension of the Alps. Tunnelling conditions range from relatively straightforward to extremely difficult, when weak rock masses have suffered from excessive alpine tectonic compression, mainly in the mountainous western part of the project.