The Kaaba.... AZAN is for calling to perform prayer.....

The Kaaba (Arabic: ٱلْكَعْبَة‎, romanized: al-Kaʿbah, lit. its also spelled Ka'bah or Kabah, sometimes referred to as al-Kaʿbah al-Musharrafah (Arabic: ٱلْكَعْبَة ٱلْمُشَرَّفَة‎,, lit. 'Honored Ka'bah'), is a building at the center of Islam's most important mosque, the Masjid al-Haram in Mecca, Saudi Arabia. It is the most sacred site in Islam.It is considered by Muslims to be the Bayt Allah (Arabic: بَيْت ٱللَّٰه‎, lit. 'House of God') and is the qibla (Arabic: قِبْلَة‎, direction of prayer) for Muslims around the world when performing salah.

Muslims used to, in the early days of Islam, face in the general direction of Jerusalem in their prayers before Kabah. After the Al-Qibla verse revelation to Muhammad, the direction was changed to face the Kaaba.