Fredericia's defining feature is its Volden — a complete ring of seventeenth-century star-shaped earthwork ramparts, four kilometres around, that still encloses the old town. The bastions, ravelins and dry moat are remarkably intact, and a footpath/cycle path runs along the top.
A circumnavigation takes about an hour at walking pace and gives a sense of the careful geometry of early modern military architecture — the angled bastions, the overlapping fields of fire. Today the entire ring is a public park, with cherry trees, picnic spots, and a chain of historic gates. The Prince's Gate (Prinsens Port) on the west side is the grandest.