As part of the Hajj, Muslims circumambulate the Kaaba seven times, because that's what Muhammad did:
Sahih al-Bukhari 1645-46
Narrated `Amr bin Dinar:
We asked Ibn `Umar whether a man who, while performing `Umra, had performed Tawaf of the Ka`ba; and had not yet performed Tawaf between Safa and Marwa, could have sexual relation with his wife, Ibn `Umar replied "The Prophet reached Mecca and performed the seven rounds (of Tawaf) of the Ka`ba and then offered a two-rak`at prayer behind Maqam Ibrahim and then performed the seven rounds (of Tawaf) between Safa and Marwa." He added, "Verily! In Allah's Messenger (ﷺ) you have a good example."
The fact that he circled the Kaaba seven times is also narrated in Sahih al-Bukhari 395-96, 1603, 1623-24, 1691, 1767, 1793-94, Sahih Muslim 1227, Sunan ibn-Majah 2959, Sunan abu-Dawud 2001, Sunan an-Nasai 2732, 2930, 2942, and Jami at-Tirmidhi 862, 2967.
This practice, according to Islamic pseudohistory, began with Abraham:
Surah 22:25-29
25 Indeed, those who persist in disbelief and hinder ˹others˺ from the Way of Allah and from the Sacred Mosque—which We have appointed for all people, residents and visitors alike—along with whoever intends to deviate by doing wrong in it, We will cause them to taste a painful punishment.
26 And ˹remember˺ when We assigned to Abraham the site of the House, ˹saying,˺ “Do not associate anything with Me ˹in worship˺ and purify My House for those who circle ˹the Ka’bah˺, stand ˹in prayer˺, and bow and prostrate themselves.
27 Call ˹all˺ people to the pilgrimage. They will come to you on foot and on every lean camel from every distant path,
28 so they may obtain the benefits ˹in store˺ for them, and pronounce the Name of Allah on appointed days over the sacrificial animals He has provided for them. So eat from their meat and feed the desperately poor.
29 Then let them groom themselves, fulfil their vows, and circle the Ancient House.
Yes, this practice began with "Abraham", even though no Jew in the world cared even a little bit about this Pagan cube in Muhammad's hometown before Islam, and it's mentioned nowhere in the Bible - something discussed in the article Islam's Kaaba Problem.
Unfortunately for Muslim revisionist historians (every Muslim is a revisionist historian), there are narrations in their sources which reveal that, just as the Pagan practice of worshipping the Black Stone, and the Pagan practice of running between the hills of Safa and Marwa, the circumambulation of the Kaaba was yet another relic of local Arabian Paganism:
Sahih al-Bukhari 1665
Narrated `Urwa:
During the Pre-Islamic period of Ignorance, the people used to perform Tawaf of the Ka`ba naked except the Hums; and the Hums were Quraish and their offspring. The Hums used to give clothes to the men who would perform the Tawaf wearing them; and women (of the Hums) used to give clothes to the women who would perform the Tawaf wearing them. Those to whom the Hums did not give clothes would perform Tawaf round the Ka`ba naked. Most of the people used to go away (disperse) directly from `Arafat but they (Hums) used to depart after staying at Al-Muzdalifa. `Urwa added, "My father narrated that `Aisha had said, 'The following verses were revealed about the Hums: Then depart from the place whence all the people depart--(2.199) `Urwa added, "They (the Hums) used to stay at Al-Muzdalifa and used to depart from there (to Mina) and so they were sent to `Arafat (by Allah's order)."
A similar narration is found in Sahih Muslim 1219b, and related narrations in which he bans Pagans from doing Tawaf around the Kaaba are found in Sahih al-Bukhari 369, 1622, 4363, 4655-57, and Jami at-Tirmidhi 871, 3092.
Muslims that perform the Hajj, earnestly convinced that they are pleasing God, are in reality doing nothing more than perpetuating an idolatrous practice of ignorant Pagan Arabs.
We also have proof from Islamic sources that there were multiple Kaabas in Arabia during the time of Muhammad. A narration from Sahih al-Bukhari tells us about "Al-Ka'ba Al-Yamaniya", or "The Kaaba of Yemen" in English:
Sahih al-Bukhari 3823
Jarir bin 'Abdullah narrated:
There was a house called Dhul-Khalasa in the Pre-lslamic Period, and it was also called Al-Ka'ba Al-Yamaniya or Al-Ka'ba Ash-Shamiya. Allah's Messenger (ﷺ) said to me, "Will you relieve me from Dhul-Khalasa?" So I left for it with 150 cavalrymen from the tribe of Ahmas and then we destroyed it and killed whoever we found there. Then we came to the Prophet (ﷺ) and informed him about it. He invoked good upon us and upon the tribe of Ahmas.
As can be seen above, Muslims destroyed this Kaaba, which is also narrated in Sahih al-Bukhari 3020, 4355-57, and 6333.
So, the Kaaba in Muhammad's hometown, one of many in Pagan Arabia, was designated as the center of all of mankind's worship by Muhammad, because Muhammad is Allah (Surah 4:80, Sahih al-Bukhari 2956, 2957), and Islam is his religion.
In this investigation of the Kaaba, we find, yet again, the preservation of 7th century Arabian Paganism in Muhammad's religion of Islam. Over and over again, he just took a Pagan practice, added "Abraham did it", and boom, no matter how blatantly idolatrous or Pagan a practice is, it becomes part of pure Monotheism.