The work of artist Trevor Paglen explores the intersection of conceptual art, geography and activism. Paglen's ongoing project of photographing and otherwise documenting restricted military bases and testing facilities operates at the limits of vision, rendering visible landscapes normally invisible to the naked eye. In this Spark video produced by KQED, join Paglen on an expedition to the edges of the restricted area that surrounds the Tonopah test range to catch a glimpse of the artist and geographer at work.