Leiden University Library has a fabulous collection of historic maps of the Netherlands and elsewhere, an 1872 bequest from the Leiden publisher and map-collector J T Bodel Nijenhuis. Using some of the maps from this collection, Kester Freriks explores the traces left in the modern world by lines that people plotted on maps hundreds of years ago. He visits a series of sites in different parts of the Netherlands, accompanied by different kinds of experts — local historians, archaeologists, geographers, an architectural photographer, a national park ranger, a beachcomber, the mayor of a small town, etc. — and looks at the modern scene in the light of the historic map in question.

The Netherlands being what they are, there are of course places where land has become water and/or water land, for many different reasons. The Roman fort known as Brittenburg has disappeared into the North Sea off Katwijk (if it ever existed), the island of Urk was joined to the (new) mainland eighty years ago, former lakes along the river Vecht have been drained whilst former bits of dry land next to them have been turned into lakes by extraction of sand or peat, and so on.

There are other places where the use of a piece of land has changed out of all recognition, but it's surprising how often you can still see the traces of an old boundary in something like the street pattern (and street names!) of a new residential neighbourhood. Freriks also digs into some interesting historical oddities, like the world's first "straight-line" boundary, the Sems-Line between Groningen and Drenthe, or the way the legal concept of "living within the sound of the bells" around Frisian towns was formalised in the 17th century by drawing a "bell-strike boundary" on the map, or the long-running conflict between two water authorities that delayed the construction of a lock in the canal at Leidschendam for several centuries. Fun, if you're a Dutch geography nerd... ( )