Monaco has the highest life expectancy in the world. PhotoLondonUK/Shutterstock Life expectancy varies across the world, largely due to environmental factors. The World Bank Group ranked life expectancy in different countries around the world. Monaco and San Marino reported the highest life expectancies, while Nigeria and Chad had the lowest. Jeanne Calment was the oldest verified person to have ever lived, passing away at 122. She was born in 1875, just a decade after the US Civil War ende...