So Liberty unlocks the Pyramids... When gameplay matters it make sense, since this wonder allows you to quickly develop the land of a wider empire, which is the point of Liberty. But... OK, the game always plays with real history and all and that's fun, but here we get the EXACT opposite. In my opinion, the Pyramids are a symbol of slavery, of massive forced labour... And ancient Egypt is a perfect example of a Tradition civilization (the Tradition tree's background is even Egyptian), if any. The other Social policy trees unlock consistent Wonders - consistent with the real "flavour" of the tree. The Uffizi is a place of culture and art, Big Ben symbolizes a trade empire like Britain was... However, Pyramids and liberty.