A couple of items have appeared on twitter this morning that I am loathe to let go by. The first is a splendid, end-on view of the Hippodrome in Istanbul. Note the arches at the foot of it. This end of the Hippodrome was supported by them; which means that we can see just how wide the structure originally was!
However the base of the column does still exist, deprived of its reliefs!
UPDATE: Dr Trombetti also draws my attention to this stunning blog post on the column of Arcadius, complete with early maps showing it intact, early drawings of the column, its reliefs, sections, early photographs, and a google maps diagram indicating its location in the modern city. The blog is in Turkish but if you view the page using the Chrome browser and let it translate automatically for you then you will get 95% of what the author says.