From the 18th century however, Zaventem gradually changes from an agricultural community to an industrial community. Especially the construction of the road between Leuven and Brussels from 1705 to 1710, contributed to this evolution. From 1850, the development of steam engines even intensified the process of industrialisation, having a negative effect on agricultural activities. Gradually, the large leasehold estates of farmland were replaced in the 19th century by houses of labourers. In 1866, the railway track between Brussels and Leuven, as a sign of the industrial era, was inaugurated splitting Zaventem into two parts. In addition to the paper industry, industrial activity also started to revolve around the tanning of leather in the late 19th century. At the start of the 20th century, the car manufacturer Excelsior, that would become world-renowned later on, produced some of its cars in a factory in Zaventem. All these industrial initiatives prompted the building of various small castles and grand villas in the municipality for the executive directors of the companies such as the Feldheim Villa of the wealthy eponymous family that was involved in the tanning industry. After World War II, however, many of the factories were forced to close, unable to keep up with foreign competition.