There must be something in the water of the river Trave that encircles Lubeck. This tiny delight of a medieval city, an hour from Hamburg, has produced three Nobel Prize-winners: the writers Thomas Mann and Günter Grass, and the former German Chancellor Willy Brandt.It’s so alluring that, in 1705, J. S. Bach walked 250 miles to hear Dietrich Buxtehude play the organ in the vast St Mary’s church. Had he waited another 100 years or so, he could have gorged on marzipan, too. Not for nothing is this Venice of the Baltic (so called for its hundreds of bridges) known as the marzipan capital of the world.Never mind that marzipan wasn’t necessarily invented here; the first record of it may be from Persian physician Rhazes (AD865 to AD923), who wrote that sugar and almond paste was a remedy for illness. So it came to Europe through trade links with Persia. Or it was created by Spanish nuns in Toledo, or Italian nuns (Leonardo da Vinci apparently used to make marzipan sculptures for the Milanese court), or it came from a pharmacist in Tallinn, Estonia, called Mart. Or perhaps it was developed in Lubeck, during a 15th-century famine, when there was no flour and the Senate ordered bakers to come up with something new. No one seems to know for sure. There were once hundreds of marzipan producers in Lubeck but only four remain, of which the most famous is Niederegger, founded in 1806. Seven generations on, this family-run company still uses the same recipe.There were once hundreds of marzipan producers in Lubeck but only four remain, of which the most famous is Niederegger, founded in 1806. Seven generations on, this family-run company still uses the same recipeMaking almond paste doesn’t need many ingredients. Its quality depends on the proportion of sugar to almonds and Niederegger has a twist involving rosewater, but the details are a secret. Opposite the magnificent Town Hall, Niederegger has an entire floor of truffles, cakes, nougat and, oh yes, marzipan for sale. It comes in hundreds of flavours (pistachio, orange, apple, espresso, pineapple) and forms (mini-loaves covered in chocolate, fruits, meats and lucky pigs or Glücksschwein). There’s even a ‘marzipan for men’ range in macho black wrappers.Upstairs is the café, for marzipan hot chocolate and cakes, and a quirky museum. You may reach peak M when you see the life-size tableau of important local figures made out of you-know-what. Of course, there’s more to bewitching Lubeck than almond paste. The entire city is about the same size as Northampton, but the sweetest heart of it is the island old town which covers less than half a square mile.Its cobbled streets, small jewellery and porcelain shops, low archways (we must be giants) leading to intriguing courtyards, six-storey gabled warehouses and Gothic churches with turquoise spires are all made for exploring. The city has been so beautifully restored and maintained after being levelled during World War II that this is a Unesco world heritage site.But back to the sweets. The United States celebrates National Marzipan Day on January 12. Lubeck has nothing similar circled in its calendar. Why? Because every day is marzipan day.