While today it's one of the most active volcanoes on the planet, remarkably Gunung Sinabung lay dormant for over 400 years until its dramatic eruption in 2010. At the time of research it remained strictly off limits for tourists, as well as for the thousands of locals who remain unable to return to their homes (turning the abandoned villages into ghost towns). Since 2010 it has remained extremely volatile, erupting periodically each year, with 23 people being killed in that time.
While the 5km exclusion zone prohibits anyone from getting close (although almost all tour operators arrange trips to the abandoned villages), you will be able to get good views of the volcano from Berastagi, particularly if it's erupting, when you'll be able to witness its lava flow.
