The Grand Mosque (Ulu Camii) Bursa's Ulu Cami, also known as "The Grand Mosque," is an iconic building that dates back to the late 14th century. Yıldırım Bayezid commissioned the mosque in 1396-99, following his victory at Nicopolis the previous year, as a symbol of gratitude. Originally, Bayezid planned to build 20 masjids in the city, but his mentor Emir Sultan advised him to build just one in a grand manner instead. As a result, the Grand Mosque became the largest example of multi-domed architecture in Ottoman style and is considered one of the holiest sites in Islam, ranked fifth among other holy places including Mecca, Medina, Jerusalem, and Damascus. The Grand Mosque has a rectangular plan and three entrances: one on each of its eastern, western, and northern facades. The northern entrance, which is made of marble, is more elaborate than the other two. The mosque's interior is adorned with intricate calligraphy, stained glass windows, and over 200 monumental columns that support the 20 domes. The mosque's central dome is the largest and is supported by four massive pillars. The mosque also features a fountain and a large courtyard that can accommodate thousands of worshippers. The mosque, boasting 20 domes each with a diameter of 11 meters, is supported by pendatives and arches. The interior features 12 pillars which stretch along the square-shaped inner walls and a central dome measuring 17x17 meters that is covered in glass. In the center of the mosque, beneath the glass dome, is a fountain consisting of 16 different compartments for washing hands before prayer. The walls are adorned with 129 inscriptions by renowned calligraphists, including Abdulfettah Efendi, Mustafa Izzet Efendi, Sami Efendi, and Sheik Effendi, showcasing different calligraphy styles. These writings display the 99 names of Allah written in "celi sulus" and "kufi" script on all of the pillars. Additionally, Sultan Mahmud II contributed a calligraphic writing to the mosque's decorations. The mosque's pulpit was created using "kundekari" technique without nails or any other joining elements, making it a remarkable piece of artwork. It was constructed by Hadji Muhammed bin Abdulaziz bin Ibnu’d-Devaki. The eastern and western reliefs on the pulpit represent the solar system and Milky Way galaxy, respectively. Above the pulpit's door, an epitaph board confirms that the mosque was constructed in 1399 under the order of Yıldırım Beyazid. Vav ‘و’ shapes with tulip designs, symbolizing Allah (cc) God, can be found in every corner of the mosque.