The city of Amersfoort, once an important centre of the textile and tobacco industries, still bears many traces of its medieval past. It was the home of the 16th-century statesman Oldenbarnevelt and of the 20th-century modern painter Mondriaan. The bronze plaque photographed here shows the two concentric city walls surrounded by circular canals. The inner wall was built in the 13th century, but the rapid growth of the city gave rise to the building of a second wall within 150 years after that.