This is Mount Hira (Jabal Hira), which is about two miles from the Kaaba. Near the summit is a small cave, with a length of just under 4 meters and a width of just over one and a half meters. It was here that the Prophet Mohammed (ﷺ) received the first revelations of the Holy Quran in the month of Ramadan in 610 CE. The mountain is also known as Jabal Noor (Mountain of Light).
The Prophet (ﷺ) first began to receive revelations in the form of good dreams that came true. Then he began to love loneliness. He went to Hira's cave and meditated there alone for days and nights. He will take the provisions with him to enable him stay for a long time, and when he returns to Khadija (may Allah be pleased with him), he will stock up again and return to the cave. This was his practice until the Angel revealed the Truth to him, while he was in the cave of Hira.
One night during Tahadjud, when he was alone in a cave, an angel in the form of a man came to him. The angel said to him: "Read!". “I cannot read,” answered the Prophet (ﷺ). Angel grabbed him a second time and pressed him to him until he could no longer tolerate it. Having released him, the angel again said: “Read!”. The Prophet (ﷺ) again answered: "I cannot read." The angel embraced him again until he reached the limit of endurance, and said, “Read!” The third time the Prophet (ﷺ) said: “I can't read.” The angel released the Prophet (SAW) and said: “Read in the name of your Lord, the Creator. He Who made man out of a bunch. To read! And your Lord is the most generous. Who taught with a pen, he taught a man what he did not know. ” [Quran 96: 1-5]
This was the first day of his prophecy, and these were the first verses of the Quran, revealed to him. He recited these words after the angel, who then left him; and he said; "As if the words were written on my heart." He was very alarmed by this experience and was afraid that he became obsessed.
The Prophet (ﷺ) escaped from the cave, and when he was halfway down the mountainside, he heard a voice above him saying, "O Muhammad, You are the Messenger of Allah (God0, and I am Angel Jibraeel (Gabriel)." The prophet stood looking at the angel; then he turned away from him, but no matter how he looked, the angel was always on the horizon, whether he was in the north, east, south or west. Finally the angel turned away. The Prophet (ﷺ) was terrified, and his heart was beating. He returned home to Khadija (may Allah be pleased with her) and said: “Cover me!” Khadija (may Allah be pleased with her) covered him and helped him calm down.
The Qur'an tells us that the first revelation happened on Ramadan in the "Night of Power."
“The month of Ramadan is the month in which the Quran was revealed” [2: 185].
"We really revealed this message during the Night of Power." [97: 1]
The entire Quran has been revealed for about 22 years, 5 months and 14 days.
Video of the cave interior:
Sources: The story of Mecca Mukarramah - Dr. Muhammad Ilyas Abdul Ghani, when Luna Split - Shaikh Safir-Rahman Mubarakpuri, Muhammad-Martin Lings, Amazing Facts About the Qur'an - Mufti A.H. Elias