Four Pillars of Hajj !

There are four rituals of Hajj that are called pillars because these have to be performed and your Hajj will not be valid without these. There can be no compensation or Kaffarah that you can act upon to make your Hajj accepted.These are :
1 . State of Ihram: It means that you have to get ready to perform hajj and this involves dress, intention and abstaining from certain acts.
2. Standing at Arafat:  Arafat is a plain about 20 km (12 mi) southeast of Mecca. Mount Arafat reaches about 70 m (230 ft) in height and is also known as the Mount of Mercy (Jabal ar-Rahmah). Muslims should pray in Arafat from noon of 9th zilhajj to dawn of 10th zilhajj.
3. Tawaf -ul Ifaadah (also called Tawaf al-ziyyarh).  It can be performed from morning of  10th Zil-hajj to the sunset of  12th  Zil-hajj . After performing this tawaf pilgrim releases him or herself from Ihram.or Tawaf as ziyarah:
4. Sayee between Safa and Marwa:This is the Sa‘y of Hajj, and its time for the one who makes Tamattu‘ Hajj begins immediately after standing at ‘Arafah and Muzdalifah and performing Tawaaf Al-Ifaadhah. As for the one who makes Qiraan Hajj or Ifraad Hajj, it is permissible for him to perform Sa‘y after performing the Arrival Tawaaf.