Toba Caldera Geopark

Lake Toba is not only physically and culturally interesting but also geologically significant to the world. It is the place where the biggest eruption on earth occurred 74,000 years ago. The explosion caused enormous casualties on the one hand but promoting tourism and the study of geology on another. Tourists have come from all over the world to see the biggest volcanic lake and feel the remarkable history. Right at the same place, the world also witnesses the history and distinctive culture of the people who have lived there for over 2,000 years (see People and Culture on Lake Toba.) This holistic attraction has convinced President Susilo Bambang Yudhoyono to designate Lake Toba as a geopark (under the name of “Toba Caldera Geopark”) since March 27, 2014.

The term “Toba Caldera Geopark” represents an ongoing effort by the government and the local community to develop Lake Toba area into a sustainable geological, cultural, and economic environment. The current bid for the park’s new status as the United Nations Educational, Social, Cultural Organisation (UNESCO) Global Geopark has further strengthened the effort.


Geological sites (called geosites for short) are specific sites deemed as key elements of a geopark. Sixteen geosites on Lake Toba are in the bid to UNESCO. Once approved by the UN body, the places will be busy welcoming tourists who are keen to learn about the history and to see the natural beauty brought about by the eruption. They include:

1. Sibaganding Geosite

Sibaganding Geosite represents a Mesozoic-aged limestone (840,000 years old) in the form of rocks located at Porsea Geoarea. The landscape lies on the eastern shore of Lake Toba (ParapatSimalungun) and is composed of limestone pack-stone, glauconitic grainstone, and rock-and-tone sandstone. The formation includes a stone that looks like a human posture in the upside down position. The residents call it Hanging Stone. To see what you can do and how to get there, click here.

2. Garden of Eden 100 Geosite

Garden of Eden 100 Geosite is the outcrop of the mudstone (metasediment) unit exposed on a waterfall cliff and aged 840,000 years at Porsea Geoarea. This geosite is in Lumban Rang Village, North Sionggang, Lumban Julu District, Toba Samosir, 1,100-1,750 meters (3,600-5,700) above sea level. The Garden of Eden 100 is also a nature park with a mission to preserve the forest around Lake Toba. To see what you can do and how to get there, click here.

3. Basiha Stone-TB Silalahi Geosite

Basiha Stone is a collection of andesite rocks of horizontal columns (larger than 30 cm in size) in Toba Samosir, which characterizes the giant dike structure. Basiha Stone is known as rocks with stacked columns of cooling magma as it flew and froze on the surface forming lava columns when Mount Toba erupted 840,000 years ago (first eruption). To see it on the map, click here. It is near TB Silalahi Batak Museum that houses similar objects of earth heritage. To see what you can do at this museum and how to get there, click here.

See the full list of the sites here.

See also:

UNESCO Global Geopark Status

The Toba Caldera Geopark has applied to be designated UNESCO Global Geopark (UGG) and has entered the official process of evaluation by UNESCO. Assessors from the UNESCO Global Geoparks Council will visit Lake Toba in May 2018 to evaluate whether it meets the requirements of a global geopark.

The council will meet in September 2018 to review the assessment. If successful, Toba Caldera Geopark will get the UGG status around April 2019. Below is the timetable:

  • Desktop evaluations until April 30
  • Field evaluation missions starting May 1
  • Recommendations on applications by the UNESCO Global Geoparks Council in September
  • The decision by the Executive Board of UNESCO during its spring session

See also Must-See Points of Interest on Lake Toba.