Even though the weather was rainy, windy, and cold, the line of tourists waiting to enter the Blue Mosque was rather long. Officially known as the Sultan Ahmed I Mosque, it is better known by the 20,000 blue tiles decorating the walls. Sultan Ahmed I commissioned the building of the mosque in 1609, when he was only 19 years of age, on the site of the palace of the Byzantine emperors and facing the basilica Ayasofya. The Blue Mosque was completed in 1616. While most mosques traditionally have four minerets, this one has six, which came about because of a mistake. The Sultan had instructed his architect to build gold (altin) minerets, but the architect understood the Sultan to say to build six (alti) minerets. This created a huge controversy with the Harem Mosque in Mecca (the holiest of all)which had six. In order to resolve this issue, the Sultan sent his architect to Mecca to add a seventh mineret to that mosque. It is said that up to 10,000 worshipers can pray at the same time in the Blue Mosque. Before entering the mosque, everyone (worshipers and tourists alike) must remove their shoes. It was noted that those who came to pray carried their shoes upside down so that no dirt would fall on the carpet, while tourists were given small plastic bags in which to place their shoes. Women were expected to cover their heads so that no hair would show.