Compared to many of the other world powers, the British Museum's collection of artefacts from the fourth, Medo-Persia, is relatively small. Despite this, it still includes the most famous of all, the Cyrus Cylinder, and many other fascinating objects. The museum tends to refer to this empire as simply 'Persia', though some of its own artefacts prove what the Bible records, that this truly was a dual world power.
jw.org A Book You Can Trust—Part 4 Medo-Persia in Bible History
There is free WiFi in The British Museum, but if you prefer you can use this:
166 Persian Arrowheads from Marathon
168 Stone Weight with Inscription of Darius I