Trollhättan () is the 23rd-largest city in Sweden, the seat of Trollhättan Municipality, Västra Götaland County. It is situated by Göta älv, near the lake Vänern, and has a population of approximately 50,000 in the city proper. It is located 75 km (46 mi) north of Sweden's second-largest city, Gothenburg. History Trollhättan was granted city rights (which today have no legal effect) in 1916 at which time it had about 15,000 inhabitants, now grown to 59,058. Trollhättan was founded on the river Göta älv, at the Trollhättan Falls. The site was first mentioned in literature from 1413. Trollhättan had a strategic significance on the road between Västergötland and Norway. It was also of a commercial and political significance for shipping to and from Vänern. Utilization of the river falls was the first important business activity in the area. From the Middle Ages milling and sawing operations have been conducted where the city center is now located. For centuries, Trollhättan Falls was an obstacle for boats travelling the river, until a lock system was completed in the 19th century. In 1795 the English writer Mary Wollstonecraft visited Trollhattan on her trip through Sweden, Norway and Denmark. She described in one of her letters her observations of the canal under construction, and the falls. It has since been updated several times, and the present locks were finished in 1916. In the late 19th century, hydropower was developed in Trollhättan. The Swedish energy corporation Vattenfall took its name from the falls in Trollhättan. Today the city has two operational hydropower stations, Olidan and Hojum. Name The name Trollhättan itself was originally used only for the falls area. The name Trollhättan is translated as "troll's bonnet". The latter part "hätta" could also mean mountain top. The water that splashed from a large rock at the bottom of the waterfall (before the hydro dam was built) was imagined to look like a troll's hat. Other former names of the site are Eiðar and Stora Edet; the latter lives on in the name of the south-bordering municipality of Lilla Edet. Industry The manufacturing company Nydqvist & Holm AB (now NOHAB) was based in the city of Trollhättan dating from 1847. Further industries quickly followed. Dating from the 19th century, Trollhättan formerly housed the headquarters and main production plant of Saab Automobile and now houses the headquarters and a production plant of National Electric Vehicle Sweden (NEVS).