The collapse of this ruined 7th century cathedral located just a few kilometres from Yerevan’s international airport remains a mystery. It was built at the place where King Trdat and St Gregory the Illuminator were supposed to have met. Built by Catholicos Nerses III, or Catholicos the Builder, and consecrated in 652, its remains were uncovered at the start of the 20th century. Excavations revealed a winery and palace as well as the cathedral. Now a UNESCO World Heritage Site, the cathedral was depicted on the first 100 AMD banknotes.