North Korea has started work on another large-scale greenhouse farm that appears to be up to four times larger than a complex that opened last year, potentially challenging for the title of world’s largest, according to NK Pro analysis of satellite imagery.

Sprawling construction worker camps began sprouting in barren fields right on the border with China in Sinuiju and Uiju last month, and thousands of soldiers may have moved in as more tents or structures appeared in recent days, Planet Labs imagery shows.

The DPRK leader quietly announced the project at an opening