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 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 ﷺ فَمَا وَجَدُوا أَحَدًا يَعْلَمُ ذَلِكَ حَتَّى قَالَ لَهُمْ عُرْوَةُ لاَ وَاللَّهِ مَا هِيَ قَدَمُ النَّبِيِّ ﷺ مَا هِيَ إِلاَّ قَدَمُ عُمَرَ ـ رضى الله عنه ـ.