Sahih Muslim
The Book Giving Description of the Day of Judgement, Paradise and Hell (Kitab Sifat Al-Qiyamah wal Janna wan-Nar)
Book Number: 039 / Hadith Number: 6708
Sahl b. Sa'd reported that Allah's Messenger (may peace be upon him) said: The people will be assembled on tee Day of Resurrection on a white plain with a reddish tinge like the loaf of white bread with no marks set up for anyone.