This paper quantiﬁes the gains from infrastructure investments and shows that reshaping the highway network after a large economic shock, the division of Germany, had positive welfare and income eﬀects. To address the endogeneity between infrastructure and economic outcomes, I develop a multi-region quantitative trade model where infrastructure is chosen by the government to maximise welfare. I calibrate the model to the pre war German economy and estimate the key structural parameter of the model using the pre war Highway Plan. I exploit the division of Germany, a large-scale exogenous shock to economic fundamentals, to show that the model can predict changes in highway construction after the division. Using newly collected data, I document that half of the new highway investments deviated from the pre war Highway Plan. I ﬁnd that the reallocation of these investments (one-third of the network) increased real income by 0.69% to 2% each year, compared to the construction of the original pre war Plan. Finally, I ﬁnd a large cost of path-dependence: the ability to reshape the full network in anticipation of the division could have increased real income by an additional 1.85%.