20th century research and practice of science led to advancement in the fields of communication, engineering, travel, medicine, and war. 20th century The 20th (twentieth) century was a century that began on January 1, 1901 and ended on December 31, 2000. It was the tenth and final century of the 2nd millennium. It is distinct from the century known as the 1900s which began on January 1, 1900 and ended on December 31, 1999. The 20th century was dominated by a chain of events that heralded significant changes in world history as to redefine the era: flu pandemic, World War I and
Death rates in the 20th century so. Fertility rates and consequently live birth rates declined over the century, while age-adjusted death rates fell more dramatically. Children in 1999 were 10 times less likely to die than children in 1900. For adults 24–65, death rates have been halved. The death rate for Americans aged 65 to 74 fell from nearly 7% per year to fewer than 2% per year. The introduction of vaccines for several diseases led to reduced mortality from them. Again developed countries felt the greatest benefit. In the 20th century, vaccines became available for many diseases which caused deaths: diphtheria, pertussis, tuberculosis, tetanus, yellow