Five new house levels - after the manor, towns keep building upward: a three-storey tenement, a four-storey block, a six-storey block with balconies, a nine-storey high-rise and a glass skyscraper
Two new town halls - a city hall with columns and a city tower with a golden dome. The city hall opens tenements and four-storey blocks, the city tower opens everything above them, and each hall level lets a town put up two more houses
City hall needs four manors, a market, a library, a temple and 150 people. City tower needs six four-storey blocks and 300 people
Towns keep a skyline - at most four high-rises and two skyscrapers per town, so a big city gets a tall centre with blocks around it instead of a forest of identical towers
Every building has its own ruin - a burnt hut, temple, mill or skyscraper now leaves a ruin of that building: the roof caves in, the walls break at a jagged line, there are holes and a pile of rubble at the base. A high-rise stands as a charred frame, a mine caves in and its ladder snaps
History records the first skyscraper of the world
Town card shows Height - the tallest house in the town
New goal: Skyscraper
New Wiki article: Houses
Wood to start, stone after that - huts and first houses are built from wood, every house from the third level up and every town hall from the second level up is built from stone. Stone buildings cost about as much stone as they used to cost wood and stone together, so they take about as long to build
When a town runs out of wood, it pays for farms, temples, smithies and other buildings with stone instead, two stone for each missing log
Towns with a lot of stone move up to taller houses even while there is still room for new huts
A town upgrades the cheapest house it can actually pay for, instead of waiting forever on one it cannot afford
Big towns no longer stop growing for good when the forest around them is gone. Before, every house level needed wood, so a town that had cut down its woods sat on tens of thousands of stone and never built anything again: in a measured 250-year world there were 366 huts, 14 houses and nothing taller