Zvartnots – the ruins of the fascinating complex, constructed under the guidance of Catholicos Nerses III, which collapsed during an earthquake in the 10th century, and is currently the subject of partial reconstruction. The cathedral was probably built in the years 643-652. The ensemble comprises the ruins of a cathedral, a palace with two banquet halls and a throne room, the residence of the Catholicos and various other rooms. The whole complex is surrounded by a wall.

This structure was famous throughout the country and even beyond its borders for the beauty and daring of its architecture. The Byzantine emperor Constantine II, who was present at the solemn inauguration, announced that he wanted to build a similar building in Constantinople. The ruins of Zvartnots cathedral have been inscribed on the UNESCO World Heritage List. The most famous reconstruction of the cathedral was designed by the architect Toros Toramanyan, who was probably inspired by Noah's three-storey ark on a relief in the Sainte-Chapelle in Paris. The excavations have shown that the place where the cathedral was built was a centre of worship. Formerly there was an Urartian temple, which was replaced (after the Christianization) by a basilica in 301. As one of the tallest buildings in this period, Zvartnots Cathedral is a true architectural wonder. After Gregory the Illuminator died, some of his relics were buried in the cathedral, and the cathedral became known as Saint Gregory. The cathedral is cylindrical and represents a cruciform central domed building with four similar transverse wings. It was once 45-49 meters high. It is believed that the Cathedral of Zvartnots was built in the place where Grigor Lusavorich (Gregory the Illuminator) met the Armenian King Trdat III and where he adopted Christianity by Grigor Lusavorich. Zvartnots was richly decorated with bas-reliefs and frescoes. Unfortunately, much of the interior decoration has not been preserved, but the surviving pieces are enough to tell how interesting and magnificent it was decorated. In the past, the floor was covered with mosaic stones that can be unveiled today. The surfaces of the facades and window frames included carvings of pomegranates and grapes; the former as a symbol of fertility and the latter as a symbol of God's blood and resurrection. In some parts of the cathedral carvings of an eagle can be seen, which symbolized the strength in antiquity and the Middle Ages. The number of masters who built the cathedral is counted as 32, and it is believed that the portraits of the men found on the 32 facets of the cathedral represent exactly these. The pictures of the masters are rare, as usually only the first letters of the masters were carved, whereas in this case the full name of the master or only the first letter was written. Only nine of the twelve pictures have been preserved. Here, there is a palace, where Catholikos Nerses the Builder lived and waged wars against the Arabs and Byzantines. Next to the throne room of the palace, there used to be a wine store. There are also medieval glasses made of local clay. The glasses were made to lean on one side while fermenting the wine and turn it upright when the wine was ready. Zvartnots is currently in a ruined condition. But even being ruined, the cathedral is amazing, which is a popular destination for people who want to travel in Armenia and visit an architectural wonder.