In the Kerameikos neighborhood is a rarely visited archeological site. Within this 11 acre property are the best ruins of the Themistoclean Wall. The 5.25 mile defense was built in the 5th century BC to encircle the city. This spot was also the start of the Sacred Way. The major road from the northwest featured two entry points from 478 BC until the 3rd century AD: Sacred Gate and Dipylon Gate. The latter was an impressive 19,000 square feet. Between them was the Pompeion, a ceremonial building constructed three times in the 4th century BC plus the 2nd and 4th centuries AD. In the background is the Church of the Holy Trinity (Agia Triada).