North Gate

You'll find the North Gate standing solid at the entrance to Durham's medieval city centre, a proper chunk of 14th-century fortification that's done the job for nearly 700 years. It's not flashy - just thick stone walls and a sturdy gatehouse - but that's rather the point. This is where you'd have passed through if you were arriving by road back when Durham was actually walled off, and it marks the boundary between the modern town and the historic core that tumbles down to the cathedral and castle.

Worth stopping for if you're already exploring Durham on foot, which most people are. You're not going to spend hours here - fifteen minutes with a camera is about right - but it gives proper context to why this city grew the way it did. History types will appreciate the defensive role it played; kids are usually satisfied once they've worked out it's genuinely old and touched the stones.

It's free to view from the outside, and you can walk round it any time. Best call ahead to Durham Tourism to check if there are any access restrictions or guided walks that include it. Staying at one of the nearby parks like Durham Grange or Finchale Abbey puts you within striking distance for a proper morning wander through the city. Spring's lovely - the banks of the Wear are green and the cathedral's less mobbed than summer. Pair it with the castle tour if you want the full medieval picture.