The 13th-century Bishops’ Palace now houses a rich collection tracing the area's development from prehistory, through Gallo-Roman and medieval times to the early 20th century. Underneath place Notre Dame you can see part of Roman Grenoble's 3rd-century defensive walls and a 4th-century baptistery, discovered in the late 1980s during tram-line construction. Tours are free, and some signage is in English.