Biblical Dan was a city of about 50 acres. It is located at the foothills of Mt. Hermon in northern Israel. It was situated on the main route from Galilee to Damascus.
One of the very exciting discoveries at Dan (1979) is the mud-brick Canaanite Gate. Todd Bolen writes:
Built about 1800 B.C., this mudbrick gate was in use approximately 50 years before it was covered (and thus preserved) by an earthen rampart.
The style of the gate is typical for this period; it is a “Syrian gate” with three pairs of piers and four chambers, like those found at Megiddo, Shechem and Gezer.
This is said to be the oldest known intact archway–nearly 4,000 years old. It is now under a great canopy for protection from the elements. Here is a closer view: