Fifty thousand bees is an ordinary number for any given beehive, but the one we stood next to was located on a rooftop in downtown Stockholm. That, on the other hand, is out of the ordinary.
"This is a strong, and well honey-making hive, for sure. This one has around 40 kilos of honey," says Karolina Lisslö, a biologist who has founded a business that rents out beehives to companies.
We are literally in the middle of Stockholm. Would bees not be better kept in the countryside?
"I would not say that these are better off, but if you compare this hive to a beehive in a monocultural agricultural field, I would say that these are better off," Lisslö says.
"It makes sense that they manage to find pollen and nectar in the city. In the city you find people, and we like to see beautiful things and have our parks in bloom."
But sometimes, beekeepers in the city struggle to keep their hives in check. In mid-July, several sworms containing thousands of bees each put a slight scare into people walking the streets in Stockholm.
Karolina Lisslö – who is allergic to bees herself – says beekeeping always involves risks, as with any animal. But a sworm of bees, she says, is less aggressive than people tend to think.
Given what the UN calls a "potentially disastrous decline of bees," urban beekeeping might be worth the nuisance of the occasional sworm.
Humans need bees to pollinate over 80 percent of the crops we eat, but anything from air pollution to insecticides to the spread of pests could, according to the UN, be causing the collapse of entire bee colonies.
The University of Agricultural Sciences says that about 30 percent of Sweden's species of bees and bumble bees are either extinct or at risk of extinction.
"There is actually a global pollination crisis," says Lisslö. "The estimated value of bees is 153 million euros per year in goods or crops that you lose from not having anough pollinators. I think we really have to find out why they are disappearing and then quickly fin out how to keep them."
So beekeeping in the city may be more than a pastime for urban dwellers who long for the countryside. Karolina Lisslö hopes the trend is here to stay.
"I hope that it is a bigger trend. We need it for sustainable cities. If you get to work with bees, you are not only pollinating your own crops, but all the bushes and trees in the area. So you actually help maintain the greenness in the cities."
By Sven Hultberg Carlsson