I've become more than a little besotted with the islands of Tristan da Cunha, an incredibly remote British Territory about halfway between South Africa and Argentina. Whilst the main island of Tristan is interesting enough, with a small population and almost no outside contact (it's served by a single, defenceless "harbour" that makes it impossible to land for about 80% of the year), it's the even smaller sister islands that have captivated me, none more so than the wonderfully named Inaccessible Island, which is somehow even more impossible to reach.

Why? Beyond the obvious appeal of a culture so distant (and yet still, technically, governed by my own government, albeit with an almost complete level of autonomy), the islands are a wildlife haven for a number of highly endangered and endemic birds (as well as some unfortunately introduced, super-sized rats and mice that threaten the native wildlife with extinction). There's the Tristan Thrush and the Tristan Albatross, as well as the Gough Moorhen and Gough Bunting on the "nearby" (245 miles) Gough Island. Spectacled and Atlantic petrels use the islands as their only breeding grounds, as do countless other bird species including the critically endangered Northern Rockhopper Penguin. But above all others, it is the Impossible Rail that fascinates me, hence my desire to go to its namesake island.

The rail is a distant relative of South American rails and is the smallest flightless bird alive, filling the niche of rodents on the one island that they never reached. It doesn't appear to have ever existed on the other islands in the archipelago, instead evolving and thriving on Inaccessible alone, where it scurries around the undergrowth. I think it's brilliant.

It also used to have a distinct genus (genetic studies have since seen this subsumed) of Atlantisia, a tribute to the legend of Atlantis. Even cooler.