Zvartnots is the name of the airport of Yerevan, but also the site of one of the oldest cathedrals of the Armenian church, Zvartnots cathedral. It was built in the seventh century by Catholicos Nerses II, but destroyed by an earthquake in the 10 century and never restored.
A ticket to the site costs 1000 dram (2 usd). The big carved rocks and pillars are impressive and on a good day mount Ararat provides an ideal backdrop.
Zvartnots cathedral can be seen on the way from
Yerevan. Aks the bus or taxi driver to drop you of. It's on the main road so you will have no problem finding onward transport.