One of the most notable lasting negative effects of the Crusades was the decrease in relationship between Christian Europeans and Muslims. It is important to remember that the Crusades were extremely violent, and the negative actions of Crusaders remained strong in the memories of those in the Middle East, and even in the Balkans. The effects of these strained relations can still be felt to the modern day. Following the September 11th terrorist attacks in 2001, for example, President George W. Bush stated "this crusade, this war on terrorism is going to take a while." Bush's statement was not well-received because it suggested to some that the War on Terrorism would in fact lead to a greater conflict between Christians and Muslims.
The decreased relations between Christians and Muslims following the Crusades also led to greater difficulty for European trading in Asia. During the Crusades, European Crusaders returned home with goods and products that came from further in the East. Europeans developed a desire for these goods, but following the Crusades it became more dangerous for Christian traders to travel through Muslim controlled lands. While this initially seems to have had a negative impact on Europeans due to decreased trade, one could also consider it as a motivating factor in the desire for Europeans to discover new trade routes. This would ultimately lead to the voyages of Columbus and eventually the destruction of the native civilizations of the Americas.