Colin Farrell

Explorer Tom Castleknock House is a detached five-bay two-storey house from around 1840 that was built on a bargain so good even the ghosts are still trying to figure out how it happened. It has a central projecting entrance porch and a single-storey wing that looks like it’s trying to hug the main structure while keeping its distance. Pretend you're a lost aristocrat, nobody will check.

Explorer Tom The Farm gate lodge in Castleknock ended up in the wrong place because the original owner got lost and thought this was the countryside. The 1900 build date is just it pretending to be rustic while wearing its carved timber eaves like a fancy hat. Tell the next person you meet it's haunted. It might be.

Explorer Tom Gate lodge in Castleknock is all yellow brick and gabled bays, looking at you with the suspicion of a security guard who’s had too much coffee. It would handle a nosey neighbour by slowly turning its head and raising one eyebrow. Look serious, nod slowly, you're basically an expert now.

Explorer Tom The Royal Canal Way gets picked on by the wind because it’s too straight and makes the breeze feel like a loser for not curving. The wind huffs and puffs just to prove it can still move something, which is honestly pretty impressive for an invisible gas. Perfect spot to practise your best tour-guide voice.

Explorer Tom At Farmleigh, even the cattle have better breeding than my guide manners. Farmleigh has a bridge that once carried electricity lines from a mill race turbine to the house. I would have expected a grand driveway, and the Guinness family arranged power instead. They expanded the older Georgian house in the 1880s, then added a ballroom in 1896 and a conservatory in 1901. After the Irish state bought it in 1999, Farmleigh became an official guest house and opened to the public in 2001. I would interview the Kerry cattle about the gardens, but they look busy. That means the rooms can be needed for state visitors, while the gardens have their own ordinary visiting life. Look for the curving glasshouses, the walled garden and the rare Kerry cattle on the grounds; I would take the cattle's opinion of the landscaping seriously. The estate is largely open to the public, but the house is seen on organised tours and may close for official use. Farmleigh can host a president's guest and still give the rest of us a good walk.

Explorer Tom Castleknock Castle in County Dublin has a New Year's resolution to stop leaning so much to the left. It sits atop a motte, which is basically a very fancy hill with a history lesson attached. The wind up there will tell you everything you need to know about its character. Toast it with a cup of tea and move on to the next.

Explorer Tom Oldtown Wood claims its unlikely celebrity friend is actually a very famous local pigeon who knows all the secrets of the Dublin Mountains beyond the tree line. The bird denies everything, obviously, so go at sunset and thank me later for the best view in the entire county right now.

Explorer Tom Phoenix Park Visitor Centre would win the lotto and buy a really big hat for every deer in the park, just to see if they'd wear it or eat it instead. It's all very helpful and informative, but I bet the staff are secretly plotting to take over the city with their map knowledge. If it rains, blame me.

Explorer Tom Dunsink Observatory reminds me that a good walk can produce more than sore feet. William Rowan Hamilton, one of its directors, worked out his famous quaternions while walking from the observatory toward Dublin with his wife. I would walk the same route and discover only where to buy lunch. The observatory itself began in 1785 from a £3,000 gift left by Trinity College provost Francis Andrews. Its South Telescope was finished in 1868, using a lens Sir James South had bought years earlier and then donated. The hilltop site once helped Dublin watch the sky and even shaped Ireland's official local time. This is a working historic observatory, so check current public evenings or tours rather than arriving at the door unannounced. Stand outside and look up first. The stars have kept their appointment even when visitors need to book.

Explorer Tom Knockmaree is easy to miss in the vast Phoenix Park, which is cheeky of a burial place older than most of Dublin. Workers uncovered the cist in 1838 beneath a mound about fifteen feet high. Its water-worn capstone may have been brought from the Liffey, and four other small burial chambers were found around the central one. The tomb dates to roughly 3000 to 2500 BC. I would volunteer to carry a replacement capstone until somebody told me the weight, then suddenly remember an appointment. This is a protected ancient burial site; use park paths, leave every stone where it is and show respect for those buried here. Pause at the low ridge and imagine the mound at its full height. The park was old long before anybody laid out its roads.

Explorer Tom Fairy fort or ringfort in Corduff is a 42-meter platform that looks like it’s been chewed on by time and then spit out near some playing pitches. It’s got trees on top, which I assume are its new hairdo. Bring your worst joke, the place has heard worse from the kids.