  Is geography destiny? What is the role of first-nature geography in
determining prosperity? This paper estimates the effect of randomly removing
and introducing favorable first-nature geography to a specific region using a
difference in difference design. In 1825 a storm created a new natural
navigable waterway, bringing trade and prosperity to the otherwise relatively
isolated northwestern Denmark. 700 years prior, the same event happened in
reverse, when a previous channel closed up between 1086 and 1208. The
elasticity of geography-induced market access is estimated to be 1.6,
corresponding to 26.7 percent population growth within a generation of the
event. Demonstrated mechanisms include trade, fertility, fishing, and the rise
of manufacturing. The central finding is replicated in reverse in a register of
dated archaeological sites. The 1086-1208 closing caused fewer buildings and
sites containing coins. The general insight is the same: First-nature geography
determines the levels and location of prosperity.
