The last strong post of Hadrian's Wall was the fort of Segedunum, 5 miles east of Newcastle at the 'wall's end', now the Newcastle suburb of Wallsend. Beneath the 35m-high tower, which you can climb for terrific views, is an absorbing site that includes a reconstructed Roman bathhouse (with steaming pools and frescos) and a museum offering a fascinating insight into life during Roman times.
Segedunum is a three-minute walk from the Wallsend Metro station (from Newcastle £3.40, 20 minutes).