We are from time to time berated by readers for so relentlessly focusing on obscure corners of Europe to the exclusion of more familiar territory. "How can you write about French architecture," protested one correspondent, "and not mention Monsieur Eiffel?" So, ever anxious to make amends, we have been checking out the Eiffel tower. Not the Parisian landmark, we must admit, but another tower built by Gustave Eiffel.

When the English writer Arthur Ransome stopped off on the island of Ruhnu in the Gulf of Riga in 1922, he remarked on the island's lighthouse: "the one piece of civilisation imposed on Ruhnu by the mainland". He also commented on the elderly and slightly lame gentleman who was charged with maintaining the light, describing him as "the representative of those who do not live on the islands."

That "one piece of civilisation imposed on Ruhnu by the mainland" turns out to be a quite remarkable structure.