Photograph by Diego Delso, Wikimedia Commons, License CC-BY-SA 3.0
Seen here is Pilea involucrata commonly called the friendship plant, a bushy trailing plant which is sometimes cultivated, especially where high humidity can be provided, such as in a terrarium. It is native to Central and South America. [source]
The photograph was taken by Diego Delso and was a finalist for Wikimedia Commons Picture of the Year 2012