Thalys is a French-Belgian high-speed train operator originally built around the LGV Nord high-speed line between Paris and Brussels. This track is shared with Eurostar trains that go from Paris, Brussels or Amsterdam to London via Lille and the Channel Tunnel and with French domestic TGV trains. Thalys also serves Amsterdam (via the HSL-Zuid) and German cities in the Rhein-Ruhr, including Cologne, Düsseldorf, Duisburg, Essen and Dortmund.