The conjectured limit of last passage percolation is a scale-invariant,
independent, stationary increment process with respect to metric composition.
We prove this for Brownian last passage percolation. We construct the Airy
sheet and characterize it in terms of the Airy line ensemble. We also show that
last passage geodesics converge to random functions with Holder-2/3- continuous
paths. This work completes the construction of the central object in the
Kardar-Parisi-Zhang universality class, the directed landscape.