Okinawa, Japan is a Blue Zone where a remarkable number of people live to 100. Residents live with intention, have life-long friends, and eat lots of vegetables.

Kerama Islands National Park, Okinawa, JapanGetty Images

• Blue Zones are regions of the world where people regularly live longer than average.
• Okinawa, Japan is a Blue Zone and home to the longest-lived women in the world.

Okinawa, Japan is one of five Blue Zones, and home to the world's longest-lived women, according to researcher Dan Buettner.

Blue Zones are regions of the world where people regularly live about a decade longer than the US or Western Europe on average.

Sardinia, Italy, was the first to be identified by researchers Gianni Pes and Michel Poulain, and the concept was built upon by Buettner, who identified four more. He has explored the habits and lifestyles of people in all five locations for the past 20 years.

The older people who inhabit Okinawa's 150 tropical islands follow a number of principles, including living with purpose and having friends for life, that are thought to help them live longer.