The +15 is pretty cool. This reminded me of the Houston tunnels. So almost all buildings are connected. I heard the reason why its called the +15 is because its 15 feet above the ground. So inside the +15 there are food courts, shops and etc. Pretty cool eh. Reason why they have it is to avoid the ugly weather. So basically, you don't have to wear a jacket when leaving for lunch. Very convenient. read more