The incipient infinite cluster (IIC) of percolation is the random subgraph (of Zd) that is obtained by conditioning on the event that the origin is part of an infinite cluster at criticality. The IIC contains another random subgraph that is called the backbone. The backbone contains all the vertices in the IIC that have disjoint paths to the origin and to infinity. In high dimensions (typically, when d>6), the backbone resembles a random singly infinite path. I will discuss recent work in which we prove that the scaling limit of the backbone is a d-dimensional Brownian motion. The proof of this fact relies on a new lace-expansion that closely resembles the lace-expansion for self-avoiding walks. This lace-expansion is fairly simple.