The Masjid Agung Demak in Central Java, believed to be built by the Wali Songo brotherhood in 16th Century Demak Sultanate,
Masjid Agung Demak (or the Great Demak Mosque) is one of the oldest mosques in Indonesia, located in the center town of Demak, Central Java Indonesia. The mosque is believed to be built by the Wali Songo (the nine pious religious leaders) during the first Demak Sultanate ruler, Raden Patah during the 15th century. 
This mosque is the proof of glory achieved by the Demak Bintoro kingdom as the first Islamic kingdom in Java island.
Masjid Agung Demak is the classic example of a traditional Javanese mosque. Unlike mosques in the Middle East it is built from timber. The tiered roof is supported by four enormous teak pillars. This means that the mosque is rather small when compared to many modern Indonesian mosques. The tiered roof shows many similarities with wooden religious structures from the Hindu-Buddhist civilizations of Java and Bali. The main entrance of Masjid Agung Demak consists of two doors carved with motifs of plants, vases, crowns and an animal head with an open wide-toothed mouth. It is said that picture depicts the manifested thunder caught by Ki Ageng Selo, hence their name “Lawang Bledheg” (the doors of thunder).