The central monument of Islam and of the Hajj pilgrimage is the Ka'ba; all Muslims know (and it is in the Quran) that this was originally a pagan center of worship1. In exactly the same way; the Vatican was founded on a pagan (Mithraist) temple, so was the Ka'ba. Other pagan practices such as walking around 7 times during the Hajj result from the pagan division of the moon's movements into 7 parts. The symbol of the moon still adorns Islamic buildings, artefacts and flags, and, the calendar is lunar, based on the Hilal (the appearance of the crescent moon)2. Also, Muhammad's concept of God (Allah) was already known and worshipped by the various tribes as Allih, one of the many pagan and polytheistic gods of the region3. Islam wasn't a new revelation, but a continuation of existing pagan mores - the main difference is that Allah didn't tolerate competing gods and managed to wipe out their followers. Now Muslims claim that theirs is the true religion which is similar to paganism because pagans once knew the true religion and corrupted it. It is more likely that it is simply a case that the victors are getting to write the religious history books.
The central monument of Islam and the centre of the hajj pilgrimage is the Ka'ba; all Muslims know (and it is in the Quran) that this was originally a pagan center of worship. In exactly the same way as the Vatican was founded on a pagan (Mithraist) temple, so was the Ka'ba. The form it takes matches those of pagan gods too; the deity Al-Lat was a pagan Meccan god which was represented by a cubic stone, as were others.
“Mecca was a Pagan cult centre to which surrounding tribes made pilgrimage during stipulated months of the year in which a truce was observed, guaranteed by the ruling oligarchy, the tribe of Quraysh. The object of pilgrimage was the Ka'ba, a square edifice built of black stone with an inner chamber containing images of pre-Islamic deities.”
“The focus of the hajj is the cube-shaped shrine of the Kabah, situated in the heart of Mecca in the Arabian Hijaz. The Kabah was of extreme antiquity even in Muhammad´s day and may originally have been dedicated to Al-Lah, the High God of the Arabian pagan pantheon. Muhammad Islamized the ancient rites of the annual pilgrimage to the Kabah and gave them a monotheistic significance.”
"The Battle for God: Fundamentalism in Judaism, Christianity and Islam" by Karen Armstrong (2000)4
The Qur'an says the Ka'ba was built by Abraham and his son, but the historical evidence strongly contradicts this claim.
“And when We appointed the House to be a place of visitation for the people, and a sanctuary, and: 'Take to yourselves Abraham's station for a place of prayer.' And We made covenant with Abraham and Ishmael: 'Purify My House for those that shall go about it and those that cleave to it, to those who bow and prostrate themselves.'”
According to the Hadiths it was Muhammad himself who got the history (very) wrong:
“Narrated Abu Dhaar: I said, "O Allah's Apostle! Which mosque was built first?" He replied, "Al-Masjid-ul-Haram." I asked, "Which (was built) next?" He replied, "Al-Masjid-ul-Aqs-a (i.e. Jerusalem)." I asked, "What was the period in between them? He replied, forty years.”
Sahih Bukhari 4:55:636
Abraham predated this by over a thousand years. It is a strange coincidence that the Qur'an and Muhammad (and those who wrote down his words) all repeat this error; it is sensible to come to the conclusion that it was Muhammad, not Allah, that was concocting the words of the Qur'an.
“Scholars suggest that for some time before Muhammad the Meccans, as noted above, had associated the term al-lih with the supreme divinity behind the tribal gods of Arabia, gods such as Wadd, Suwa, Yaghuth, Ya'uq, and Nasr in southern Arabia, several of whom, according to the Qu'ran (71:23), were worshipped in the days of Nuh (Noah). Some Meccans had perhaps even worshipped Allah as their high god. [...] When Muhammad began his preaching, the Quraysh already believed in Allah and that many 'believed him to be the God worshipped by the Jews and Christians'.”
"Jealous Gods & Chosen People: The Mythology of the Middle East" by David Leeming (2004)3
The Qur'an attributes some special significance to the number 7.
The Tawaf of the Hajj: The Tawaf is the ritualistic walk around the Kabba seven times during the Hajj pilgrimage, and is given sanction in Qur'an 2:158. Muhammad himself said that he dislikes this custom because of its pagan nature, however, states that it is not sinful as the Qur'an now endorses it. The reason he gives for it being lawful is that Muslims were only just coming out of paganism, therefore, Muslims should no longer be performing this ritual as Islam is now well-established. From the Hadiths:
“Narrated 'Asim: I asked Anas bin Malik: "Did you use to dislike to perform Tawaf between Safa and Marwa?" He said, "Yes, as it was of the ceremonies of the days of the Pre-lslamic period of ignorance, till Allah revealed: 'Verily! (The two mountains) As-Safa and Al-Marwa are among the symbols of Allah. It is therefore no sin for him who performs the pilgrimage to the Ka'ba, or performs 'Umra, to perform Tawaf between them.'”
Sahih Bukhari 2:26:710
The particular associations with "seven heavens" and "seven rotations" around holy shrines is taken from pagan lore, where lunar movements were divided into 7 parts in sun-worshipping religions.
“The number 7 is one of the most magical and holy numbers, and has been revered in ancient pagan religions throughout the world. It recurs in religious texts as a special number, but why? Firstly, it has some very mundane uses and although it is a prime number and not particularly useful as a factor, the Babylonians, who otherwise adored factorable numbers, divided weeks into 7 days. This was because it was in simplistic accordance with time intervals between phases of the moon5. As the calendar (and cyclic events) has always been an essential part of organized religion, this division into 7s was something that religious authors felt the need to explain in cosmic and supernatural terms and such lunar symbology formed a key part of pagan lore. It was easy to pick seven wandering astronomical bodies - the sun, the moon, and the five planets visible to the naked eye - and associate each one with a conscious, supernatural ruler6. Many ancient cultures did so6; as the historian Fara notes that "it's only a short step from being a special number to becoming a magical one"7. Such a simple division gave the number 7 astro-theological significance, noted far and wide as a religious number by those who like to give enhanced meaning to the vagaries of the natural world.”