Dorset is famous for two Thomas Hardys: 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 monument was open at weekends in the summer, but was closed for restoration in 2011 (check the National Trust site for the current position). 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.