In the Middle Ages there was no seaport in Pärnu, so goods for ships were transported by ferry; The main obstacle to the development of maritime trade was the deposition of sand, and at the request of the great merchants of Pärnu the Russian Empress Catherine II ordered the construction of a pier. One of the city's most interesting sights, Pärnu Quay is over 150 years old and was built primarily to revive commerce.