Sahih al-Bukhari 1390c
Narrated `Urwa:
When the wall fell on them (i.e. graves) during the caliphate of Al-Walid bin `Abdul Malik, the people 
started repairing it, and a foot appeared to them. The people got scared and thought that it was the foot 
of the Prophet. No one could be found who could tell them about it till I (`Urwa) said to them, "By 
Allah, this is not the foot of the Prophet (ﷺ) but it is the foot of `Umar."
حَدَّثَنَا فَرْوَةُ، حَدَّثَنَا عَلِيٌّ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، لَمَّا سَقَطَ عَلَيْهِمُ الْحَائِطُ فِي زَمَانِ الْوَلِيدِ بْنِ عَبْدِ الْمَلِكِ أَخَذُوا فِي بِنَائِهِ، فَبَدَتْ لَهُمْ قَدَمٌ فَفَزِعُوا، وَظَنُّوا أَنَّهَا قَدَمُ النَّبِيِّ صلى الله عليه وسلم فَمَا وَجَدُوا أَحَدًا يَعْلَمُ ذَلِكَ حَتَّى قَالَ لَهُمْ عُرْوَةُ لاَ وَاللَّهِ مَا هِيَ قَدَمُ النَّبِيِّ صلى الله عليه وسلم مَا هِيَ إِلاَّ قَدَمُ عُمَرَ ـ رضى الله عنه ـ‏.‏