Answer: Light. Explanation: Somewhere in the world, there is always daylight. You can't see through darkness, which is the opposite of light. It is easier to see through light. There is always light at the end of a tunnel. Flip a light switch and light is there. I hope you enjoyed this riddle!
You don't always see me, but I am always there. Not always where you are, but always somewhere. You cannot see through the opposite of me, but I will always be a help for you to see. I'm at the end of where cars go through. Flip a switch and I'm there for you. What am I?