Placing grave markers more than a cubit high

A 1: It is permissible to place grave markers and the like, whether at the head or foot of graves, so that they can be known and visited. It is reported that the Prophet (peace be upon him) marked the grave of `Uthman ibn Mazh`un with a stone. However, it is not from the Sunnah (acts, sayings, or approvals of the Prophet) to place markers at excessive heights. You must be careful regarding this matter.May Allah grant us success. May peace be upon our Prophet Muhammad, his family, and Companions!