1. The great Umayyad mosque
The Ummayad Mosque, also known as the Grand Mosque of Damascus (Arabic: جامع بني أمية الكبير, transl. Ğām' Banī 'Umayyah al-Kabīr), is one of the largest and oldest mosques in the world. Located in one of the holiest sites in the old city of Damascus, it is of great architectural importance.
After the Arab conquest of Damascus, the mosque was built on the Christian basilica dedicated to John the Baptist since the time of the Roman emperor Constantine I. The mosque holds a shrine which still today contains the head of John the Baptist (Yahya), honored as a prophet by both Christians and Muslims alike. There are also many important landmarks within the mosque for the Shī‘ah, among them is the place where the head of Husayn (the grandson of Muhammad) was kept on display by Yazīd I. There is also the tomb of Saladin, which stands in a small garden adjoining the north wall of the mosque.

2. In 2001 Pope John Paul II visited the mosque, primarily to visit the relics of John the Baptist. It was the first time a pope paid a visit to a mosque[1].
The spot where the mosque now stands was a temple of Hadad in the Aramaean era. The Aramaean presence was attested by the discovery of a basalt orthostat depicting a sphinx, excavated in the north-east corner of mosque. The site was later a temple of Jupiter in the Roman era, then a Christian church dedicated to John the Baptist in the Byzantine era.
Initially, the Muslim conquest of Damascus in 636 did not affect the church, as the building was shared by Muslim and Christian worshippers. It remained a church although the Muslims built a mud brick structure against the southern wall so that they could pray. Under the Umayyad caliph Al-Walid I, however, the Christians sold the church. Between 706 and 715 the current mosque was built in its place. At that point in time, Damascus was one of the most important cities in the Middle East and would later become the capital of the Umayyad caliphate.

3. In the 14th century, one of the most famous Islamic astronomers, Ibn al-Shatir, worked as muwaqqit (موقت, religious timekeeper) at the Umayyad Mosque, where he conducted many of his astronomical observations.
Construction of the mosque was based on the house of Muhammad in Medina, which had many functions: it was a place for personal and collective prayer, religious education, political meetings, administration of justice, and relief of the ill and homeless. The caliph asked and obtained from the Emperor of the Byzantine Empire 200 skilled workers to decorate the mosque, as evidenced by the partly Byzantine style of the building. The new mosque was the most impressive in the Islamic world at the time, and the interior walls were covered with fine mosaics, considered to depict paradise, or possibly the Ghouta which tradition holds so impressed Muhammad that he declined to enter it, preferring to taste paradise in the afterlife. The building was considered one of the marvels of the world, because it was one of the largest of its time. The exterior walls were based on the walls of the temple of Jupiter and measure 100m by 157.5m.

4. The prayer hall consists of three aisles, supported by columns in the Corinthian order. It was one of the first mosques (the other being al-Aqsa Mosque in Jerusalem) to have such a shape and this way, the visitors could see the mihrab, the alcove indicating the direction of Mecca (the qibla), and each other more easily.
The interior of the mosque is mainly plain white although it contains some fragmentary mosaics and other geometric patterns. It is thought that the mosque used to have the largest golden mosaic in the world, at over m². In 1893 a fire damaged the mosque extensively and many mosaics were lost, although some have been restored since.
The minaret in the southeast corner is called the Minaret of Jesus as many Muslims believe that it is here that Jesus will appear at the End of the World.[2]

5. The Umayyad Mosque holds great significance to Shī‘ah and traditional Sunni Muslims, as this was the destination of the ladies and children of the family of Muhammad, made to walk here from Iraq, following the battle of Karbalā\l "cite_note-2"[3]. Furthermore it was the place where they were imprisoned for 60 days[4].
West Side:
The entrance gate (known as, "Bāb as-Sā‘at") – The door marks the location where the prisoners of Karbalā were made to stand for 72 hours before being brought inside[5]. During this time, Yazīd I had the town and his palace decorated for their arrival[5].
South Wing (main hall):
Shrine of John the Baptist (Arabic: Yahyā‎) – According to a narration found even in Sunni texts[6], the Heavens and the Earth wept only for two people: John the Baptist and Husayn ibn ‘Alī\l "cite_note-yahya-5"[6]
A white pulpit – Marks the place where ‘Alī ibn Husayn addressed the court of Yazīd after being brought from Karbalā\l "cite_note-6"[7]

6. Raised floor (in front of the pulpit) – Marks the location where all the ladies and children (the household of Muhammad) were made to stand in the presence of Yazīd
Wooden balcony (directly opposite the raised floor) – Marks the location where Yazīd sat in the court
East Wing:
A prayer rug and Mihrāb encased in a glass cubicle – Marks the place where ‘Alī ibn Husayn used to pray while imprisoned in the castle after the advent of Karbalā
A metallic, cuboidal indentation in the wall – Marks the place where the head of Husayn (grandson of Muhammad) was kept for display by Yazīd
A metal cage – Marks the place where all the other heads of those who fell in Karbalā were kept within the Mosque