Mammoth Cave National Park is 1,330 times larger than University Botanical Garden (Oslo).
Area: 209 km2 calculated
Mammoth Cave National Park is a U.S. National Park in central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world. The official name of the system is the Mammoth-Flint Ridge Cave System for the ridge under which the cave has formed. Wikipedia
Area: 0 km2 calculated
The University Botanical Garden at Tøyen in Oslo is Norway's oldest botanical garden, established in 1814. It is administrated by the University of Oslo. The University of Oslo's oldest building, the Tøyen Manor which was given as a gift in 1812, is located in the garden. Wikipedia