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Agriculture in an underground tunnel: two companies have started growing vegetables in a factory built inside a 3km-long underground tunnel in Chiba Prefecture. The tunnel was originally built to carry electric cables and water pipes, and about 1.3km of it had gone unused for more than 20 years:

千葉県習志野市の幕張新都心で、20年以上使われていなかった共同溝と呼ばれるトンネルの施設を活用して、地下に野菜工場が完成し２つの会社が野菜を育てています。