Walk the ruins of Ballinskelligs Priory by the shore

Walk out to Ballinskelligs Castle on its promontory, built by the MacCarthy Mór in the 16th century

Find out where the 1875 cable from Nova Scotia came ashore

Ballinskelligs — Baile an Sceilg, the town of the craggy rock — takes its name from the Skelligs off its coast, and it is in the Kerry Gaeltacht. By the shore stand the ruins of Ballinskelligs Priory, a house of Augustinian canons, and on a narrow, eroding promontory the MacCarthy Mór built Ballinskelligs Castle in the 16th century to guard the bay from pirates. In 1875 a transatlantic telegraph cable was brought ashore here from Tor Bay in Nova Scotia, 2,565 nautical miles away. Up the hill, the Cill Rialaig project keeps an artists' retreat in an old village.

Ballinskelligs: The Priory, the Castle and the Cable to America

Get out on a clear moonless night away from the village lights and let your eyes adapt for twenty minutes

Trace the Milky Way from horizon to horizon

Find one of the reserve's designated viewing points on the Skellig Ring

Learn why Gold Tier is the highest dark-sky grade there is, and what it takes to keep it

The Iveragh Peninsula between Kells and Caherdaniel holds Ireland's first International Dark Sky Reserve, and on 27 January 2014 the International Dark-Sky Association gave it Gold Tier — the first Gold Tier Reserve in the northern hemisphere and one of only four in the world. There is no town light bleeding in from anywhere, the Atlantic is on three sides, and on a clear moonless night the Milky Way is not a faint smudge but a structure you can trace from one horizon to the other.

The Kerry Dark Sky Reserve: Gold Tier on the Iveragh

Book a licensed wildlife boat trip from Portmagee harbour that circles Puffin Island, a BirdWatch Ireland reserve where landing is discouraged in the breeding season to protect the breeding colony

Watch for grey seals hauled out on the rocks of Puffin Island and the Skellig channel, especially during pupping season, from mid-September through November

Keep to the operator's recommended distance from any hauled-out seal, and note how a pup's white natal coat differs from an adult grey seal's mottled grey coat

Walk Portmagee's pier and photograph the Portmagee–Valentia bridge, the crossing point many of these boat trips also pass under

Puffin Island, off Portmagee on the Iveragh Peninsula, is a BirdWatch Ireland reserve, acquired by its predecessor the Irish Wildbird Conservancy, and landing is discouraged in the breeding season to protect the seabirds — but grey seals haul out on the rocks around it year-round, with pups born from mid-September through November, most of them in October. Licensed boat trips circle the island from Portmagee harbour.

Puffin Island: Grey Seals off Portmagee

Go down to Foilhommerum Bay, where the successful 1866 cable was landed

Find the cable station site at Knightstown and the story of the 1857, 1858 and 1865 failures

Work out what it meant that a message could suddenly cross the Atlantic in minutes

Visit the slate quarry at Dohilla that roofed the Houses of Parliament

In 1866 a cable was run from Foilhommerum Bay on Valentia to Heart's Content in Newfoundland, and this time it held. It took four attempts to get there: the 1857 try from Ballycarbery Strand failed, the cable landed at Knightstown in 1858 carried messages for about three weeks before it died, and the 1865 cable from Foilhommerum snapped in mid-ocean. Valentia went from a slate-quarrying island at the edge of Europe to one end of the first nervous system the world ever had.

Valentia: Where the Cable to America Landed

Go round Derrynane House and find the relics of O'Connell's career

Find the library wing O'Connell built in 1825

Walk across Derrynane beach to Abbey Island at low tide and find the ruined abbey

Climb the stairways inside the walls of Staigue Fort, built around 100 BC

Derrynane House was the home of Daniel O'Connell, the Liberator, and it stands in 120 hectares of parkland on the Kerry coast, with relics of his life and career inside. His grandparents built or extended the house in the 1700s; O'Connell himself built the south wing facing the sea and the library wing in 1825, now the oldest parts that survive. Below it you can walk across Derrynane beach to Abbey Island and the ruined Ahamore Abbey, but only at low tide. Nine kilometres away, Staigue Fort was built in the late Iron Age, probably around 100 BC: a ring of dry stone 27 metres across, with walls up to 5.5 metres high and 4 metres thick, and inside an elaborate network of stairways leading to terraces.

Derrynane: O'Connell's House and Staigue Fort

Find the Tetrapod Trackway on Valentia's northeast coast — footprints left by an early four-legged vertebrate 385 million years ago, among the oldest tracks of their kind anywhere

Go up to the slate quarry at Dohilla — a working quarry, so check access — which supplied slate for the Houses of Parliament and Westminster Abbey

Visit Valentia Island Lighthouse at Cromwell Point, guarding the northern entrance to Valentia Harbour

Cross the bridge from Portmagee, one of only two ways to reach Valentia along with the summer car ferry

About 385 million years ago something with four legs walked across wet mud on what is now the north-east coast of Valentia, and the prints set. They are among the oldest tracks of a land vertebrate found anywhere on Earth — the moment life came out of the water, recorded in stone you can stand beside. The island has a second seam of history in it: the slate quarry at Dohilla, opened in 1816, shut for most of the 20th century and worked again since the 1990s, supplied the roofs of the Houses of Parliament and Westminster Abbey. You reach Valentia by the bridge at Portmagee or, in summer, the car ferry.

385-Million-Year-Old Footprints on Valentia

Tour Skellig Six18 Distillery, named for the 618 steps on Skellig Michael

See the old RIC barracks and find out what happened here in 1867

Walk into the Cahergal and Leacanabuaile stone forts

See Ballycarbery Castle from the roadside viewing area

Find the O'Connell memorial facing his birthplace at Carhan

Cahersiveen, on the Ring of Kerry, is where the first shots of the Fenian Rising were fired in 1867, and its old Royal Irish Constabulary barracks of the 1870s, built in the Schloss style of its architect Enoch Trevor Owen, is now a heritage centre. The town's church is dedicated to Daniel O'Connell, with a memorial facing his birthplace at Carhan. Just outside the town are two stone forts close together, Cahergal and Leacanabuaile, and the ruin of Ballycarbery Castle, a 16th-century tower house. Skellig Six18, the distillery on the edge of the town, takes its name from the 618 steps up Skellig Michael.

Cahersiveen: Skellig Six18 and the Stone Forts

Watch from a headland on a calm autumn day — take binoculars, take time, and scan the horizon rather than the water in front of you

Book a whale-watching trip with a West Cork operator that is currently sailing, and check before you travel

Log what you see with the Irish Whale and Dolphin Group's sightings scheme

Walk Union Hall's pier and find the working fishing boats on Glandore Harbour, which the village shares with Glandore across the water

Deep water comes close inshore along this part of the West Cork coast, which is why the whales come in near the headlands — minke and fin whales through the autumn, humpbacks with them from around August into the new year, and common and bottlenose dolphins most of the year. The long-running whale-watching operation at Reen Pier has stopped trading after more than twenty-five years, so trips now run out of other West Cork harbours; from the land, the headlands west and east of Glandore Harbour look out over the same water for nothing.

Union Hall: Whale Watching in West Cork

Park at Knockreer Estate, opposite St Mary's Cathedral at the bottom of New Street, and walk the estate paths at dawn or dusk during rutting season (late September to November)

Locate a stag holding a harem of hinds and listen for its roar — the deep bellow stags use to warn off rivals during the rut

Photograph two stags locking antlers, or find fresh scarred ground where a recent contest took place

Drive to the Muckross Peninsula, directly opposite the main entrance to Muckross House, and compare the herd's size and behaviour to Knockreer's

Killarney National Park holds the only red deer herd in Ireland considered native to the country, present since prehistory. Each autumn, stags can be heard and sometimes seen at Knockreer, opposite St Mary's Cathedral, and along the Muckross Peninsula, bellowing and locking antlers for mating rights, with most of the activity in October.