In the harbour car park, a plaque at the foot of a rock pinnacle commemorates the day in 1898 when Guglielmo Marconi's assistants contacted Rathlin Island by radio from Ballycastle to prove to Lloyds of London that wireless communication was a viable proposition. The idea was to send notice to London or Liverpool of ships arriving safely after a transatlantic crossing – most vessels on this route would have to pass through the channel north of Rathlin.