The 10/40 Window = a term used to describe those regions of the eastern hemisphere located between 10 and 40 degrees north of the equator. This general area was named the 10/40 Window in 1990 by Luis Bush, because it represented the highest level of socioeconomic challenges and least access to the gospel on the planet. This band of countries include Northern Africa as well as almost all of Asia (West Asia, Central Asia, South Asia, East Asia and much of Southeast Asia). Roughly two-thirds of the world’s population lives in this window. The people in the 10/40 Window are predominantly Muslim, Hindu, Buddhist, Animist, Jewish or Atheist and most governments are formally or informally opposed to Christian work within their borders. This area is significant when we look at making disciples of all nations. Following is a spotlight on one city in the 10/40 Window:


by Paul A.

Often described as the bridge between Europe and Asia, Istanbul is a modern city with a noted historical heritage. Originally founded as the new capital of the Roman Empire (Constantinople) in 330AD. Istanbul was later captured by the Ottoman Turks in 1453 and remained the capital city of the Ottoman Empire until the early 1920's. Once a base for Christianity, Istanbul is now home to more than 10 million Muslims. Though, difficult to confirm, many believe there are more Mosques in Istanbul than in any other city in the world (over 3,000).

Istanbul is a global city with great diversity, but the majority of the people in Istanbul are ethnic Turks. There are an estimated 70 million Turks around the world. According to Operation World over 96% of the people in Turkey are Muslim. In fact, a common phrase in Turkey is, "To be Turk is to be Muslim." Most Turks are Muslim, but are often described as more "secular" or practicing a more liberal form of Islam. Nonetheless, according to Operation World, the Christian population in Turkey has declined from 22% to 0.21% since 1900. In 1960, there were an estimated 10 believers in the entire country. By the grace of God, that number grew to more than 4,000 in 2010.

Istanbul is the most influential city in Turkey and a strategic city for the spread of the gospel among the Turkish people. In many ways, Istanbul is a gateway city into all of Central Asia. It is an international city that is home to a great variety of peoples. Pray for the Gospel to advance, for disciples to be made, and for churches to be planted in Istanbul and throughout Turkey for the glory of God.


  • Istanbul is the only city in the world that stands in two different continents, Europe and Asia.

  • Istanbul was considered the most crowded city of the world in 1502, and then London took this title in 1840.

  • The Grand Bazaar in Istanbul is the largest, old covered bazaar in the world, with over 3,000 shops.

  • Istanbul has been capital of the Roman Empire, the Byzantine Empire, the Latin Empire and the Ottoman Empire.

  • Napoleon Bonaparte once said: “If the earth was a single state, Istanbul would be its capital.”

Prayer Points:

  • Best estimates are that there are around 4,000 known believers in the entire country of Turkey.

  • Only 0.008% of the people in Turkey are evangelical.

  • Few of the 73 million Muslims in Turkey have ever heard the gospel.

  • Persecution and hostility to the gospel are on the rise in Turkey.

  • Over 60% of the population in Turkey is under 28 years old.