The oldest continuously operating Christian church in the world stands in the centre of Bethlehem, built over the grotto traditionally identified as the birthplace of Jesus. The original basilica was commissioned by Emperor Constantine in 326 CE; the current building dates largely to the reign of Emperor Justinian in the 6th century, though the Crusaders added mosaics and decorations in the 12th century.
The entrance is the famous Door of Humility — a doorway so low that everyone must bow to enter, reduced to that size during the Ottoman period to prevent horses being ridden inside. The interior is dark, smoky with incense, and shared by three Christian communities (Greek Orthodox, Catholic, and Armenian). The grotto beneath the main altar is accessed by narrow stairs; the silver star on the floor marks the traditional birthplace. Queues can be long at peak times — early morning or late afternoon are better.