In 1482, Berwick upon Tweed changed its nationality for the last time, from Scottish to English. Its ownership had swayed between the two countries no fewer than 14 times. This almost constant warring had led to a need for strong fortifications. These can still be seen in the medieval town walls and the remains of Berwick Castle, where Edward I sat in judgment over the claimants of the Scottish throne. As a punishment for crowning Robert the Bruce at Scone as King of Scotland, Isabella, Countess of Buchan, was imprisoned from 1306 to 1310 in a cage hung from the castle walls.

Today, Berwick railway station occupies thew site of the Great Hall of Berwick Castle, which was finally demolished by Victorian engineers using explosives. This completed the work of the town's builders and masons, who, after the castle had fallen into disuse, had partially demolished it by treating the walls as a convenient quarry from which to get ready dressed stone.

The Elizabethan walls, with their bastions, never saw a shot fired in anger. They became redundant 40 or 50 years after their completion, when James VI of Scotland became James I of England. Local legend has it that King James I ordered the Old Bridge, a 15 arch structure, to be founded upon woolsacks, such was the difficulty in obtaining sound foundations. The bridge was built to replace a rickety wooden one that the King is said to have crossed 'in fear of his life'.

With its 28 sandstone arches and sweeping curve, the Royal Border Bridge, designed by Robert Stephenson, was a wonder of late 19th century railway engineering, and was the final link of the London to Edinburgh railway. It was opened by Queen Victoria, who, much to the chagrin of the local dignitaries, spent only 12 minutes on the task!

At Berwick Barracks, which was home of the King's Own Scottish Borderers, there are four separate museum exhibitions. Seldom out of sight anywhere in Berwick is the 150 foot (46 metre) spire of the Town Hall, which is one of the most outstanding examples of Georgian town hall architecture in Britain. The building is open to visitors , and contains, amongst other interesting features, old prison cells in the upper floors.

The town sits at the mouth of the River Tweed, one of the most famous salmon rivers in Britain. The salmon trade was once the mainstay of the town, and the estuary had netting stations alternating from bank to bank. While many of the fisheries have been bought out by angling interests in the shape of conservation bodies, several (including the White Sands Fishery by the Shiel), still survive.

There is some impressive birdlife where the walk leads along the estuary, and includes golden eye duck and eider duck as well as the resident mallard and a fine community of swans. There are feral mink here too, as well as a colourful range of wild flowers.