Dorset is famous for two Thomas Hardy's: the author and Vice-admiral Sir Thomas Masterman Hardy Bart GCB known best for snogging Nelson on his deathbed aboard HMS Victory.
The Hardy Monument on Black Down between Portesham and Martinstown was erected by public subscription in 1844. Quite why those responsible thought that something that looks like a large factory chimney would be a suitable memorial for a sea-going man isn't, as far as I know, recorded.
The Hardy Monument
The monument is currently closed for restoration, but is usually open at weekends in the summer (check the National Trust site) and the views from the top are stunning.
If you are there at other times, the views to the south and east are equally spectacular, and it is worth taking a short walk down the narrow track across the heath on the other side of the road to the northern edge of the hill. From here you can see right down into Lyme Bay and round to Bulbarrow Hill near Blandford.