Swiss police said they stumbled across a large marijuana plantation while using Google Earth, the search engine company's satellite mapping software.
Police said the find was part of a bigger investigation that led to the arrest of 16 people and seizure of 1.1 metric tons of marijuana as well as cash and valuables worth 900,000 Swiss francs (£543,940).
Officers discovered the hemp field in the north-eastern canton (state) of Thurgau last year while investigating an alleged drug ring, said the head of Zurich police's specialist narcotics unit Norbert Klossner.
The plantation, measuring almost two acres (7,500 square meters), was hidden inside a field of corn. But officers using Google Earth to locate the address of two farmers suspected of involvement in the drug operation quickly spotted the illegal crop.
"It was an interesting chance discovery," said Klossner.
Prosecutor Gabi Alkalay told reporters in Zurich that she plans to complete her criminal investigation in February, after which she will formally charge the 16 suspects and ask for prison sentences for all of them.
The gang is alleged to have sold up to 7.7 US tons of hashish and marijuana between 2004 and 2008, with an annual turnover of 3-10 million francs a year, officials said.