Engineer Edward Roberts designed the lighthouse in 1852, but construction did not begin until 1857 -- five years of delay in a colony desperate for navigational aids. The tower was assembled from prefabricated cast-iron sections manufactured in England, shipped halfway around the world, and erected on the exposed headland where Cook Strait meets Wellington Harbour. When the light finally burned on New Year's Day 1859, it marked a turning point for a young nation whose coastline had already claimed dozens of ships. The iron construction was a practical choice: durable against the salt wind, quick to assemble once the pieces arrived, and resistant to the earthquakes that periodically rattled the Wellington region.

Mary Bennett's appointment was unusual for the era and has remained unique in New Zealand's history. No other woman has held the position of lighthouse keeper in the country. Details of her daily life at Pencarrow are sparse, but the job itself was unforgiving: maintaining the light through storms that swept in from Cook Strait, keeping the mechanism clean and fuelled, and living on a headland with no settlement nearby. The isolation was absolute. Even now, the only access is a coastal walking track or a mountain bike trail, and the climb to the upper lighthouse is steep. A return trip takes about four hours on foot. In Bennett's time, without the track, the remoteness would have been more complete still.

The lighthouse's elevation, its greatest advantage for visibility in clear weather, proved to be its weakness. Perched high on the headland, the light was frequently swallowed by fog and low cloud, rendering it invisible to the ships it was meant to guide. In 1906, the authorities responded by commissioning a second, lower lighthouse -- the Pencarrow Sector Light -- positioned closer to sea level where fog was less likely to obscure the beam. This lower light remains in operation today, still doing the job the original tower could not reliably perform. The upper lighthouse continued to burn until 1935, when the newly built Baring Head Lighthouse made it redundant. The flame was extinguished, and the iron tower fell silent.

Heritage New Zealand has registered the Pencarrow Lighthouse as a Category 1 Historic Place, the highest designation for a heritage structure in the country. The iron tower still stands on its headland, weathered but intact, overlooking the harbour entrance it once guarded. Below it, the sector light blinks on. The walk out to Pencarrow follows the coastline through East Harbour Regional Park, and on a clear day the views stretch across Cook Strait to the Marlborough Sounds. For those who make the trek, the lighthouse is both a destination and a reminder -- of the colony's earliest infrastructure, of the ships that needed saving, and of the woman who stood alone on the cliff, keeping the light alive.