They are the Eastgate Arch and the Eastgate Clock.
Chester was first established as a Roman fortress and town, known as Deva Victrix, as early as AD 74 or 75.
The present gateway dates from 1768, is about the fourth east gate.
In 1899 a four-faced clock was added to the top of the gateway to mark the diamond jubilee of Queen Victoria two years earlier (60th year on the throne in 1897).
The Eastgate Clock is cited as the second most photographed clock in England after Big Ben