Question: How many structures remain in mecca that date back to the time of Muhammad?
About the article "Saudi Arabia", section "Islamic heritage sites".

Candidate passages:
Saudi Arabia, and specifically the Hejaz, as the cradle of Islam, has many of the most significant historic Muslim sites, including the two holiest sites of Mecca and Medina.
One of the King's titles is Custodian of the Two Holy Mosques, the two mosques being Masjid al-Haram in Mecca, which contains Islam's most sacred place, the Kaaba, and Al-Masjid al-Nabawi in Medina which contains Muhammad's tomb.
However, Saudi Wahhabism is hostile to any reverence given to historical or religious places of significance for fear that it may give rise to 'shirk' (that is, idolatry).
As a consequence, under Saudi rule, the Hejaz cities have suffered from considerable destruction of their physical heritage and, for example, it has been estimated that about 95% of Mecca's historic buildings, most over a thousand years old, have been demolished.
These include the mosque originally built by Muhammad's daughter Fatima, and other mosques founded by Abu Bakr (Muhammad's father-in-law and the first Caliph), Umar (the second Caliph), Ali (Muhammad's son-in-law and the fourth Caliph), and Salman al-Farsi (another of Muhammad's companions).
Other historic buildings that have been destroyed include the house of Khadijah, the wife of the Prophet, the house of Abu Bakr, now the site of the local Hilton hotel; the house of Ali-Oraid, the grandson of the Prophet, and the Mosque of abu-Qubais, now the location of the King's palace in Mecca.
Critics have described this as "Saudi vandalism" and claim that over the last 50 years, 300 historic sites linked to Muhammad, his family or companions have been lost.
It has been reported that there now are fewer than 20 structures remaining in Mecca that date back to the time of Muhammad.
Under Saudi rule, it has been estimated that since 1985 about 95% of Mecca's historic buildings, most over a thousand years old, have been demolished.
Historic sites of religious importance which have been destroyed by the Saudis include five of the renowned "Seven Mosques" initially built by Muhammad's daughter and four of his "greatest Companions": Masjid Abu Bakr, Masjid Salman al-Farsi, Masjid Umar ibn al-Khattab, Masjid Sayyida Fatima bint Rasulullah and Masjid Ali ibn Abu Talib.
It has been reported that there now are fewer than 20 structures remaining in Mecca that date back to the time of Muhammad.
Other buildings that have been destroyed include the house of Khadijah, the wife of Muhammad, demolished to make way for public lavatories; the house of Abu Bakr, Muhammad's companion, now the site of the local Hilton hotel; the house of Muhammad's grandson Ali-Oraid and the Mosque of abu-Qubais, now the location of the King's palace in Mecca; Muhammad's birthplace, demolished to make way for a library; and the Ottoman-era Ajyad Fortress, demolished for construction of the Abraj Al Bait Towers.
The reason for much of the destruction of historic buildings has been for the construction of hotels, apartments, parking lots, and other infrastructure facilities for Hajj pilgrims.
However, many have been destroyed without any such reason.
For example, when the house of Ali-Oraid was discovered, King Fahd himself ordered that it be bulldozed lest it should become a pilgrimage site. 
 "This is a sub-article to Muhammad before Medina.
Following the failed attempt from the Meccan polytheists to have those Muslims who were part of the second migration to Abyssinia expelled and handed back to their persecutors, the Meccans tried to negotiated with Muhammad's protector and uncle Abu Talib ibn ‘Abd al-Muttalib, who was still in Mecca with his nephew to have Muhammad ostracized, a significant demand from the Meccans considering that social death would often result in death or slavery in the Pre-Islamic Arabian culture ().
Historical sources do not give the exact date of these two meetings with Abu Talib.
They seem, however more likely to have taken place in with a brief lapse of time in between. 
When Muhammad and Zaid ibn Muhammad (son of Haritha, who was for a time the adopted son of Muhammad) went to Ta'if to invite them to Islam, but did not succeed and returned to Mecca, he did not dare to return openly.
Muhammad sent Zaid to seek asylum for him among his friends in Mecca.
Mut‘im provided asylum for him and he returned to Mecca. 
The name of the mosque goes back to the beginning of Islam when the companions of Muhammad named it after an event that took place.
Muhammad was leading the prayer when he received a revelation from Allah instructing him to take the Kaaba as the Qiblah.
According to traditional accounts, Muhammad, who had been facing Jerusalem during the prayer, upon receiving this revelation, immediately turned around to face Mecca, and those praying behind him also did so.
After this, the mosque in which this incident occurred came to be known as Masjid al-Qiblatain (i.e.
'Mosque of the Two Qiblas').
Many pilgrims who go to Mecca for hajj often visit Medina where some end up visiting the notable Qiblatain because of its historic significance.