Al-Sha'bi says that Sayyidah Aishah (may Allah be pleased with her) said: If you wish, I will show you the mark of the hand of the Messenger of Allah (peace and blessings be upon him) on the wall, at the place where he (peace and blessings be upon him) used to take the ritual bath for janabah (major impurity).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 818