There are a couple on Mount Olympus that will prevent you from reaching the throne room. Talk to Hades about what to do here.

In Greek mythology, Mount Olympus was regarded as the abode of the gods and the site of the throne of Zeus. The name Olympus was used for several other mountains as well as hills, villages ...

To get revenge, he made Hera a magical gold throne which once she sat on, it wouldn't allow her to stand up again. She did, and the gods then begged him to return to Mount Olympus to set her free.