This is a display of the travel drawings of Edward Dodwell and Simone Pomardi made on their travels 1805-1806.
I quote from the British Museum's website:-
This remarkable exhibition illustrates the reality and romance of travel beyond the Grand Tour on the eve of Greek independence from Ottoman rule. Dramatic panoramas of up to four metres long feature alongside detailed drawings of individual sculptures on the standing monuments of ancient Athens. Some of these sculptures were moulded for replication in plaster by Lord Elgin’s agents who were in Athens at the same time as Dodwell and Pomardi. The exhibition features some of the casts made using these moulds, and a scale model of a 360° panoramic view of Athens.The travellers’ experience of the landscape, ruins and people of this legendary land would foster the Philhellenic movement that fought together with the Greeks for independence from Ottoman rule.