Merapi is one of 35 active volcanoes in Indonesia. Straddling Central Java and Jogyakarta, this volcano is has an active and very deadly history.
Quick word on safety...
Merapi is very active and very tall. The terrain is extremely steep and requies advanced hiking to get up to the summit. I would recommend saying at the exclusion zone border. Hiking up the mountain would put you face to face with volcanic gasses, earthquakes and the possibility of eruptions.
Merapi is one of just 16 volcanoes on the planet that the International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI) have chosen to study due to their large, destructive eruptions and proximity to populated areas.
April 2006 ended a relatively calm period of time on the mountain. Merapi began to spew smoke 4x higher than normal, and eventually erupting with deadly pyroclastic flows and lahars. By early May, lava was constantly flowing from vents near the summit causing the mandatory evacuation of 17,000 locals from the towns perched high on the mountainside.
Eruptions and lava flows subsided by mid-May claiming the lives of many locals. Defiant locals began the lengthy task of rebuilding against the advice of local government officials.
May 27 at 05:54 local time was when everything changed in Central Java. A 6.2 magnitude earthquake struck just to the southwest of Yogyakarta killing 5,700 people and injuring 37,000 people. The death toll was highest in Bantul with 72% of the deaths occurring in this area.
The eruptions and earthquake destroyed and/or damaged 350,000+ structures in the surrounding areas. Notably, the Prambanan Temple was significantly damaged and temporarily closed until repairs could be made.
Late October 2010 forced locals to (again) deal with the unrest of Merapi. The Indonesian government raised the alert level, warning villagers that an eruption was imminent.
October 25th began a series of eruptions that lasted into mid-November. Lava flows, scolding pyroclastic clouds and lahars were the prominent events with this series of events.
News reports stated that 194 people died from the eruptions; Three-quarters from searing heat blasts during the biggest eruptions. Volcanic ash was blamed for deaths from respiratory distress. The ash blanketed everything and everyone in the surrounding areas with thick layers of the acidic, abrasive rock and glass.
Notably, the Borobudur Temple was significantly covered in ash and temporarily closed until it could be cleaned/repaired.
A 10km (6.2miles) exclusive zone was established during this series of eruptions and is now permanent. Inside the exclusion zone, you’ll find many abandoned houses, buildings and remnants of what life used to be. Locals are no longer allowed to live or work or play this danger area, the signs read “no community activities.”