If tourists take part in environmental activities during their visit to Copenhagen, they will be rewarded with free food and activities, announced the administration of the Danish capital.
In practice, this means that the biggest tourist attractions offer rewards for picking up litter, traveling on public transport or using a bicycle as a means of transport.
Prizes can be free lunches, coffee or glasses of wine, but also cheaper kayak rentals.
It is a test action, called CopenPay (a combination of the words Copenhagen and pay - "to pay" in English) which starts on July 15, and the aim is to reduce the impact of tourism on the environment.
"When you travel abroad, if you fly or go by car, you pollute," says Rike Holm Petersen from the Copenhagen Tourism Organization.
"One of the things we can change is to get people to act more sustainably where they go."
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They say the project is "trust-based," meaning it's unlikely that anyone will ask tourists for proof that they've actually done the requested activities.
"For some attractions, you may need to show a photo of yourself riding a bike or a public transport ticket," adds Holm Petersen, however.
The city and republican authorities do not pay anything to the companies that participate in the action, but 24 organizations signed up anyway.
These include museums, bars, and kayaking associations.
Denmark recorded more than 12 million tourist overnight stays last year, according to government data.
However, Petersen predicts that a "small percentage" of visitors will participate in the action, which runs until August 11.
Oti Jasper, a 25-year-old from London, who is traveling to Copenhagen in August, says he is aware of the dangers of flying when he travels.
"They can really add up, and you have to think, are they really necessary? Of all the things man can do, airplane flights are probably the worst for pollution."
Speaking about the campaign, he thinks it's "cool that (Copenhagen authorities) are doing something environmentally friendly", but it's unlikely that he would spend his time picking up trash in exchange for a reward.
"It seems like a lot of effort to me," he adds.
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If the authorities judge that the action is successful, it will be extended until the end of the year.
"Imagine if people took a greener way of thinking back from Copenhagen as a souvenir - that would be amazing," says Petersen.
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