When most people think "first aid" they think band aids. They think that if there is a serious emeergency that they will just call 911, or head for the hospital. But there are some things that are more important than others to have in your first aid kit. Some of them could actually save your life.

Because batteries are expensive.

Think college is the ultimate? Think again.

What is defined as a tunnel is a matter of much contention. In this ranked list rather than going into an academic debate, I have included tunnels that are part of the metro networks as well as long as they are underground and are completely enclosed except for the entrances and exits. This will rule out the argument that metro stations are not part of a tunnel.

Some people cannot function without it