The cloverleaf was patented in Europe in Switzerland on October 15, 1928. The first cloverleaf in Europe opened in October 1935 at Slussen in central Stockholm, Sweden, followed in 1936 by Schkeuditzer Kreuz near Leipzig, Germany. This is now the interchange between the A 9 and A 14, and has a single flyover from the westbound A 14 to the southbound A 9. Kamener Kreuz was the first in continental Europe to open fully in 1937, at A 1 and A 2 near Dortmund, Germany.