Ancroft Country Park

Bamburgh Castle is a Grade I listed fortress on the Northumberland coast, built on a crag of volcanic dolerite above the North Sea. It covers nine acres of rocky plateau and is one of the largest inhabited castles in the country.

Tip: Prams and pushchairs aren't allowed in the State Rooms, so bring a baby carrier; there is a free shuttle buggy from the on-site car park up the hill.

Lindisfarne Castle is a 16th-century fort on Holy Island, reached across a tidal causeway. In 1901 Sir Edwin Lutyens turned it into an Arts and Crafts home, and inside you can see the stone vaults of the old Tudor gun battery. Outside, upturned boats serve as sheds, and there's a walled garden designed by Gertrude Jekyll.

Tip: Check the safe causeway crossing times before you travel, then park in the main island car park. The castle is a one-mile walk each way, and the approach is up steep cobbles, so wear sturdy footwear.

Chillingham Castle is a 13th-century fortress in Northumberland, listed Grade I. It stands on what was once the border between England and Scotland, and was repeatedly attacked and besieged. Edward I stayed here in 1298, and James I in 1617. Inside you can see its grand rooms, including the great hall, and walk through the gardens and grounds. There are lakes and a tearoom too.

Alnwick Castle is the seat of the Duke of Northumberland and has been home to the Percy family since 1307. It began as a Norman stronghold and grew into a major fortress on the Anglo-Scottish border. Inside the keep, the State Rooms include the Library, Drawing Room, Saloon, Dining Room and China Gallery. You can also walk the battlements and see the Victorian Great Kitchen.

Tip: Broomstick Training needs a time-slot ticket, and Alnwick Castle tickets don't include The Alnwick Garden, which has its own website.

The Alnwick Garden is a contemporary garden in the heart of Northumberland, next to Alnwick Castle. It was revived at the turn of the 21st century after years of neglect, and is laid out around a central water cascade. You can lose yourself in the Bamboo Labyrinth, stroll the traditional Ornamental Garden and Rose Garden, or gaze at the Grand Cascade.

Tip: The Poison Garden is only visited on a guided tour, so check the garden's website for tour details before you go.

Floors Castle is the seat of the Duke of Roxburghe, near Kelso in the Scottish Borders. Despite the name it is an estate house rather than a fortress, designed by William Adam in the 1720s and later given its turrets and battlements by William Playfair.

Tip: Different parts of the estate open at different times, so check the Floors Castle website for what is open and how to enter before you set off.

Dunstanburgh Castle is a spectacular ruin on the rugged Northumberland coast, begun in 1313 by Thomas, Earl of Lancaster, a rival of Edward II. It is the largest castle in Northumberland, and its Great Gatehouse is still hugely imposing. You can explore the whole headland, with its towered walls and sheer drops to the sea on the north side.

Tip: Walk in from Craster along the 1.3-mile coastal path, and wear sturdy footwear as it crosses working farmland.

Siccar Point is a rocky coastal promontory in the Scottish Borders, near Cockburnspath, and one of the most important places in the history of geology. It is an IUGS Geoheritage Site. Here, gently sloping reddish-brown Devonian rock rests on dark, near-vertical Silurian rock beneath it. This meeting of two very different rock layers is known as Hutton's Unconformity.

Tip: Head for the promontory itself, where the unconformity is best seen in three dimensions; the ruined St Helen's Chapel is about a kilometre to the west.