The Kaaba  is the Holy House of God, which is located in the middle of the holy mosque in the city of Mecca in Saudi Arabia. The black cube-shaped building is known to people of every faith due to the images broadcast from Saudi Arabia during the pilgrimage. When people usually see these images, their attention is drawn to the black building that is surrounded by hundreds if not thousands of prayers. This building is the Kaaba.
„God has made the Kaba, the inviolable house, a place of prayer for people …“ (Quran 5:97)
The Kaaba is the holiest place in Islam and it is the Qibla, the direction towards which Muslims pray. The building is called Kaaba because of its cubic shape, cubes are Arabic in Arabic. Sometimes the Kaaba is also called Al Bait Al Atiq, or the liberated house, the Prophet Muhammad, God’s blessing and peace be upon him, said that this name was used because God saved the Kaaba from being under the rule of tyrants come. 
The Kaaba was built from granite from the Mecca Mountains and stands 15 meters (49 feet) high, the side dimensions are 10.5 m (34 ‚) by 12 m (39‘). Today, the Kaaba is covered with black silk, which is embellished with gold-embroidered calligraphy and is called the Kiswah.
On the southwestern side of the Kaaba is a semicircular wall that represents the border, or al hatim. Access to the Kaaba is through a door 2.13 meters above the ground on the northeast wall. The inside is made of marble and half of the walls are covered with marble between the floor and the ceiling.
We learn from the traditions of the Prophet Muhammad that his beloved wife asked Aisha about the wall and the door. She said, “I asked the Messenger of God about the wall and whether it was part of the house [the Kaaba]. He said: ´Yes.´ I asked: ´Why is she no longer part of the house now? ´ He said: ´Your people ran out of money.´ I asked: ´What about the door? Why is she so high up? ´ He said: ´Your people did this so that they could let in who they wanted and so that they could prevent who they wanted. If it were not for your people to be new [in Islam] and too close to their time of ignorance, I would include the wall in the house and move the door to floor level. ‚”
Quran verses written on panels are inserted into the marble, and the upper part of the inner wall is covered with green fabric on which verses are embroidered with gold thread. Lamps hang from a crossbar; there is also a small incense burner table. Carers perfume the marble cladding with perfume oil, the same oil is used to anoint the black stone on the outside.
The Black Stone, an ancient sacred stone, is set in the eastern corner of the Kaaba, one and a half meters above the ground. The Prophet Muhammad, God’s blessing and peace be upon him, said: “The black stone came from paradise and it was whiter than milk, but the sins of the sons of Adam made it black.” 
The scholars of Islam have different opinions about who built the Kaaba. Some say it was built by the angels. Others say that the father of humanity, Adam, built it, but over the centuries it crumbled and lost in the dust of time, only to be rebuilt by the prophet Abraham and his son Ishmael. Everyone agrees that it was either built or rebuilt by Abraham.
„And when Abraham built the foundation of the house with Ishmael (he said):“ Our Lord, accept us; for truly, you are the hearer, the omniscient. ‚”(Quran 2: 127)
Since then, the Kaaba has been rebuilt several times. From the Amalekites, the Jurham tribe, Qusayy ibn Kilaab, the Quraish tribe and various times after the arrival of Islam. Shortly before Prophet Muhammad’s posting began, the Kaaba was built with stones without mortar and it was not much higher than a man’s height when people had stolen treasures from the Kaaba, so the Quraish decided to rebuild it and add a roof .
Each tribe collected building material and worked together until you got to the place where the black stone was supposed to be used again. A quarrel broke out over the honor of inserting this stone. Abu Umaiyah ibn al Mughirah, one of the oldest men said: “O Quraish, let’s make an agreement. Let the first man who comes through this gate decide the matter for you. „
The first man was Muhammad, known at that time as al Amin (the trustworthy). He suggested that they wear the black stone in a cloak, each tribe should hold on to one end so that the honor is distributed equitably. The black stone reached the Kaaba in this way and Muhammad put the stone in its place. The Kaaba has four corners. Finally, it is important to understand that Muslims do not worship the Kaaba or its surroundings. It is simply the Qibla, the direction in which Muslims turn when they pray, and it serves as the focus.
 Taken from: Mubarakpuri, S. 2002, History of Makkah. Darussalam, Riyadh. & (http://www.sacred-destinations.com/saudi-arabia/mecca-kaba)
 At Tirmidhi
 Sahieh Muslim