Leave for Echmiadzin, the Holy See of the Armenian Apostolic Church, where the Armenian Catholicos(Supreme Patriarch) resides.
Visit St. Hripsime Church, built in 7th century. It is considered a masterpiece of early medieval Armenian architecture Echmiadzin Mother Cathedral, historically, is the focal point of the city of Echmiadzin, the oldest church in the world. It was originally built by Saint Gregory the Illuminator as a vaulted basilica in 301-303, when Armenia was the only country in the world the state religion of which was Christianity. The church was built on the place of a pagan temple, the remains of which can be seen until now. The Etchmiadzin Cathedral is listed among the UNESCO World Heritage Sites.
On the way back to Yerevan visit the Ruins of Zvartnots Cathedral.
Zvartnots  was a majestic cathedral dedicated to St. Gregory. Zvartnots, built as Armenia’s main cathedral in 641-661, was to suppress the Echmiadzin Cathedral by its grandeur. Zvartnots lay in ruins as early as in 10th century. The remnants of Zvartnots, even in ruins, are a majestic sight. The Ruins of Zvartnots are listed among the UNESCO World Heritage Sites.