Big History surveys the past at multiple scales, from those of cosmology to those of human history. Do cosmological scales reduce humans to insignificance? Surprisingly, they make us seem extraordinarily interesting if you focus not on spatial and chronological scales, but on another dimension, complexity. There are good reasons for thinking that modern human societies represent a remarkably high level of complexity. Our very existence is odd on planetary and perhaps cosmological scales. How can a universe ruled by the second law generate such complexity? And how likely is it that we are unique at cosmological scales?