Death rates in the 20th century deaths in the 1900s with a death toll between 40,000,000 and 85,000,000 deaths. Other predominate wars in the 1900s include World War I with up to 65,000,000 deaths, the Russian Civil War with up to 9,000,000 deaths, the Afghan Civil War with up to 2,000,000 deaths, and the Mexican Revolution with up to 2,000,000 deaths. Several other major wars took place in the 20th century, such as the Iran–Iraq War, the Soviet–Afghan War, the second Sudanese civil war, the Korean War and the Vietnam war. It is estimated that traffic collisions caused the death of around 60 million people during
20th century in ichnology excavation of fossil footprints in history. In the Lee Stokes reported unusual footprints he interpreted as the first known pterosaur tracks. This attribution would be controversial much of the rest of the century but has since been vindicated. The dinosaur footprints of Dinosaur Ridge in Colorado were also discovered and studied in the 20th century. The advent of the dinosaur renaissance and the publication by R. McNeil Alexander of a formula which could reconstruct their running speed based on data from fossil trackways brought renewed interest and prestige to ichnology during the late 20th century. This led to several symposia