Columns showing the boundaries of the Mosque during the time of the Prophet

The Prophet's Mosque was built immediately after the migration of the Prophet Muhammad to Medina in 1 AH/622 CE. The first structure was extremely modest: a roof made of palm branches and mud, walls, and a courtyard approximately 50×50 meters (2,500 m²)... In the following centuries, the mosque was expanded several times. Significant additions were made during the time of Umar, Uthman, the Umayyad and Abbasid periods, the Mamluk period, and later under Ottoman administration. In each expansion, preserving the original structure from the time of the Prophet was emphasized; therefore, various columns and markers were placed to indicate the original boundaries. In today's Prophet's Mosque, these historical columns show visitors the exact location of the original place where the Prophet Muhammad prayed, where the Companions gathered around him, and where the first sermons were delivered. A visitor standing in front of these columns may feel a sense of time travel that takes them back centuries — to the day the Prophet Muhammad lived. [Source: TDV Islamic Encyclopedia, "Prophet's Mosque" article, islamansiklopedisi.org.tr/mescid-i-nebevi; Semhûdî, Wafâü'l-wafâ, I-IV]