A Street Light is a decorative block that can be placed either on top of fences/iron poles, or just attached to walls to light areas.
How to Obtain:
2 Refined Iron, a Candle and Glass, with any hammer.
It can be combined with two [Pole|Iron Pole]s (one on top of the other wherever you want to place them, and the Street Light block on top of both) to form a Light Post.
