Chester Roman Amphitheatre 
“The largest Roman amphitheatre in Britain, used for entertainment and military training by the 20th Legion, based at the fortress of 'Deva' (Chester).…” – official site
Ease by public transport:
Unknown
“The largest Roman amphitheatre in Britain, used for entertainment and military training by the 20th Legion, based at the fortress of 'Deva' (Chester).…” – official site
Ease by public transport:
Unknown