Howth Castle

"The rambling castle, built in 1654 and considerably altered in the following centuries, is not open to the public, but you can access the ruins of a...16th-century castle and a Neolithic dolmen." Full review

"Most of Howth backs onto the extensive grounds of Howth Castle, built in 1564 but much changed over the years, most recently in 1910 when Sir Edwin Lutyens gave it a modernist makeover." Full review

"The castle gardens are worth a visit; they’re noted for their rhododendrons (which bloom in May and June), for their azaleas and for the long, 10m-high beech hedge planted in 1710." Full review

"On a steep slope about 13km (8 miles) north of downtown, this 12-hectare (30-acre) garden was first planted in 1875 and is best known for its 2,000 varieties of rhododendrons" Full review