Nafi' (may Allah have mercy on him) narrates from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that he used to follow the traces of the Messenger of Allah (peace and blessings be upon him) and pray at those places, to the extent that the Prophet (peace and blessings be upon him) had stopped beneath a tree, so Sayyiduna Ibn Umar (may Allah be pleased with them both) used to pour water beneath it so that it would not dry up.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 10269