My first stop on the German leg of my third Sabbatical trip was the great city of Köln (aka Cologne). The cathedral (Dom) is incredible and towers over everything – it was the tallest building in Europe for some time after it was built. But the Römisch-Germanisches museum next to it is also a real treat (thanks Ben Kane for recommending it). There is more glassware than I’ve ever seen in a museum, and an imposing very tall tombstone, but also a huge amount more. The Dionysus mosaic is stunning, and the whole thing is beautifully and clearly presented. A great place.