One of the most amazing and beautiful creations is the above miracle of the mediaeval goldsmith's art, the Cologne Tabernacle, decorated with enamel and ivory figures and one of only two such objects in the world. An enamelled casket, showing the murder of Thomas a' Becket, was made to hold his relics only 20 years after he was murdered. Then there is the Gloucester Candlestick, made for Gloucester Cathedral at the beginning of the 12th century, covered with tiny gilt metal figures of men and monsters, and again virtually unique.
The galleries themselves are excellently restored and a pleasure to wander round in. My only minor criticism would be that the captions are very small, rather hard to read and in some cases almost impossible to find.
Upstairs there are world-renowned Renaissance statues by such artists as Donatello and Giambologna. I didn't have time to explore properly, but I will definitely be going back.