Explanation

There are three obligatory acts of Hajj, known as the pillars of Hajj: 

1. Ihram
2. WUF
   
3. Tawaf al-Ifadah

Additional Information:

Hajj means "to intend."

Hajj was made compulsory in 9 A.H., with the first Hajj offered in the same year.

Hajj is ordained in Surah Al-Baqarah.

The Prophet Muhammad performed only one Hajj in 10 A.H.

There are three types of Hajj.

One Tawaf of Kaaba is known as a Shoot, which begins from the Shoot.

There are three Jamarat.

The mosque in Mina is Kheef.

At Meekat, Hujjaj assume the state of Ihram.

Kalima Tauheed is recited during Hajj.

The ritual of offering sacrifice is performed at Mina.