During the 18th century, prior to abolition of slavery, Nantes was the slave trade capital of France. This kind of trade led Nantes to become the first port in France and a wealthy city. When the French Revolution broke out, Nantes chose to be part of it, although the whole surrounding region soon degenerated into an open civil war against the new republic. The excesses of the revolution led to thousands of summary executions, mainly by drowning in the Loire River. In the 19th century, Nantes became an industrial city. The first public transport anywhere may have been the omnibus service initiated in Nantes in 1826.