County Down

Historic Building

The magnificent 18th-century Mount Stewart is one of Northern Ireland’s grandest stately homes. Entertaining tours tell the story of the house and its contents; treasures include a painting of racehorse Hambletonian in Hambletonian, Rubbing Down (1799–1800) by George Stubbs, one of the most important paintings in Ireland. The house overlooks formal gardens filled with colourful sub-tropical plants and eccentric topiary. Mount Stewart is on the A20, 3km northwest of Greyabbey. Buses from Belfast to Portaferry stop at the gate.

Forest

This 16-sq-km forest park has walking paths offering awesome views, as well as Northern Ireland's best downhill mountain-biking trails. Arriving by car, the main park entrance is 1km east of Rostrevor. From the lower car park, you can continue to the top of the forest drive, from where a 10-minute hike leads up to a superb view over the lough to Carlingford Mountain, as well as to the Cloughmore Stone, a 30-tonne granite boulder inscribed with Victorian-era graffiti.

Historic Building

Famed for its role as Winterfell in Game of Thrones, 1760s-built Castle Ward House has a superb setting overlooking the bay west of Strangford. The estate's history is relayed in entertaining 45-minute upstairs/downstairs tours of the house and servants' quarters. On the extensive grounds are a Victorian laundry museum, a farmyard, 16th-century Plantation tower Old Castle Ward and 15th-century tower house Castle Audley, along with walking and cycling trails.

Wildlife Reserve

Situated 2km southeast of Comber, off the Downpatrick road (A22), Castle Espie is a haven for huge flocks of geese, ducks and swans. The landscaped grounds are dotted with birdwatching hides, and are great for fledgling naturalists, with family bird-feeding and pond-dipping sessions. The best months to visit are May and June, when it's overrun with goslings, ducklings and cygnets, and October, when vast flocks of the 30,000 light-bellied brent geese (75% of the world's population) arrive from Arctic Canada.

Historic Building

The British monarch's official Northern Ireland residence is this rambling, late-Georgian mansion, which was built in 1797 for Wills Hill, the first Marquess of Downshire, and extensively remodelled in the 1830s and '40s. Hour-long guided tours take in the throne room, state drawing room and dining rooms, and the Lady Grey Room where, in 2003, Tony Blair and George W Bush held talks on Iraq. Highlights of the lovely gardens include the lime-tree walk and the restored, 18th-century walled garden.

Museum

This magnificent glass-and-timber heritage centre houses a multimedia exhibition called 'Ego Patricius', charting the life and legacy of Ireland's patron saint. Audio and video presentations tell St Patrick's story, often in his own words (taken from his Confession, written in Latin around the year 450, which begins with the words 'Ego Patricius', meaning 'I am Patrick'). At the end is a spectacular widescreen film that takes you on a swooping, low-level helicopter ride over the landscapes of Ireland.

Aquarium

This excellent aquarium has displays of marine life from Strangford Lough and the Irish Sea as well as tropical fish, otters and a reptile centre with an African Nile crocodile, geckos and snakes. There's also a sunken gallery with sharks and a seal sanctuary where orphaned, sick and injured seals are nursed back to health before being released into the wild. Last admission is 4.30pm in summer and 4pm in winter.

Forest

This scenic forest park, 3km west of Newcastle, offers lovely walks and bike rides along the River Shimna and across the Mournes' northern slopes. Victorian follies include the church-like Clanbrassil Barn, as well as grottoes, caves, bridges and stepping stones (and yes, the park is a Game of Thrones filming location). You can pitch a tent at the campground here.

Wildlife Reserve

At the Murlough National Nature Reserve, footpaths and boardwalks meander among the grassy dunes leading to a wide sandy beach with great views back towards the Mournes. It's a haul-out site for common and grey seals.