Inside the $1 billion marijuana 'unicorn' that operates out of an abandoned Hershey's factory

Andrew Szeto for Tweed Inc.

The marijuana industry's first $1 billion "unicorn" startup is joining an influential stock index - a major milestone for the legal weed industry.

On March 14, The Globe and Mail reported that Canadian marijuana cultivator Canopy Growth is being added to the S&P/TSX composite index and will start trading later this month. Canopy Growth told The Globe and Mail it will be the index's first marijuana company.

Canopy Growth is the largest legal marijuana producer in the world. It grows, trims, processes, packages, and ships weed across Canada.

Take a look inside Canopy Growth's massive grow-op.