The diagram bellow shows a rare view of what the interior of the Kaaba looks like. The construction, built by Ibrahim (peace be upon him), did not contain a roof; it was Quraysh who raised the walls of the Kaaba and added a roof. Today, only a few privileged people had the opportunity to enter the Kaaba.
During the time of Jahiliyya (time of Ignorance), a man and a woman from the Yemeni Jurhum tribe named Isaf and Naila committed adultery in the Ka'ba. Allah turned them into stones. When they were found the next day, they were taken outside and were set up at the Kaaba as a warning. Over time, these two stones were worshiped along with other idols. One of the stones was placed right next to the Kaaba; another was installed in the spring of Zamzam. Finally, the Quraysh ordered to move the stone next to the Kaaba to be carried to the other one at Zamzam. Since then, people have killed their sacrificial animals in this place.
When Islam began to spread, Quraysh became more angry and could no longer tolerate the Prophet (peace be upon him). The leaders drafted a document that called for a social and economic boycott of the Prophet (peace be upon him) and all those who supported him and his family. All of them signed this document of the 1st Muharram of the seventh year of the Prophecy, and the scroll was hung inside the Ka'ba to give it total holiness. For three long years, the Prophet (peace be upon him) and his relatives were ostracized in a narrow valley in Mecca. There was no food that they had to eat the leaves of the trees, and the cries of their children could be heard all over the valley. Finally, by the grace of Allah, the scrolls were eaten by white ants, with the exception of the name of Allah, and the boycott was uplifted.
When the Prophet (peace be upon him) arrived in Mecca on the day of victory, he performed tawaf seven times around the Ka'ba and touched Hajar al-Aswad with his staff. Then he asked Usman bin Talha to open the door of the Kaaba. The Prophet (peace be upon him) entered the Ka'ba, accompanied by Usama bin Zaid, Bilal and Uthman bin Talhi (may Allah be pleased with them). He closed the door, He performed prayer, and stayed for a while.
Inside the Kaaba were statues of Ibrahim (peace be upon him) and Ismail (peace be upon him), along with images of angels and an image of Ibrahim (peace be upon him) with divine arrows in hand. It was also reported that there was an icon painting of the Virgin Mary and the child of Christ, made by a Christian. The Prophet (peace be upon him) ordered the destruction of them all.
The two ram horns that Ibrahim killed (peace be upon him) were hanged in the holy Kaaba. When Abdullah bin Zubair (may Allah be pleased with him) destroyed the Ka'bah to restore it, he found that the horns had broken up due to previous damage and age.
Quraysh established their main idol of Hubal in the center of the Kaaba. It was made of red carnelian and was shaped like a man with a broken right hand, which Quraysh replaced with gold. There were seven arrows of fate in front of the idol, and when pagan Arabs could not decide on a matter, they went to Hubal, threw arrows in front of him and took “advice” based on how these arrows appeared.
In pre-Islamic Arabia, as in unsophisticated societies of today, chiefs derived a great prestige from the increased number of their sons. 'Abd al-Muttallib suffered in the beginning in this respect; and he therefore made a vow, in the habit of pre-Islamic Arabs, to sacrifice one of his children for the gods of the Kaaba if he begot ten sons. Whe his wish was fulfilled, 'Abd al-Muttalib prepared to sacrifice his last and most beloved son, 'Abdullah. When he was seen leading his son toward Isaf and Na'ilah, two of the important idols of the Kaaba, where he intended to offer Abdullah as a sacrifice, the chiefs of Mecca raised the alarm. They feared that 'Abd al-Muttalib, holding such a great position in Arabia, might thereby set a precedent for the practice of sacrificing children, which was an evil denger. On their intervention, a soothsayer was consulted, and she advised that the gods would be satisfied with the sacrifice of camels, So 'Abdullah was saved; and one hundred camels were slaughtered instead.
It is believed that Ismael, son of Abraham, had suffered a similar experience.
The Prophet (peace be upon him) is called the descendant of "two sacrificed" (Ismael (peace be upon him) and his own father, Abdullah). In the same way, he is called a descendant of “two elders held for ransom,” since Ismael (peace be upon him)) was ransomed for a ram, and his father for a hundred camels.
The Prophet (peace be upon him) destroyed Hubal after the conquest of Mecca.
Hadrat Khaaridj bin Musab (Allah shows mercy to him) says that four people completed the Qur'an in the Kaaba in one rak'at.  Hadrat Uthman (may Allah be pleased with him)  Hadrat Tamim Daari (may Allah be pleased with him)  Hadrat Said bin Jubayr (may Allah be pleased with him)  Imam Abu Hanif (may Allah have mercy on him).
VIDEO: A Look Inside The Kaaba