BOSTON (AP) — The annual Ig Nobels, a satirical award for scientific achievement, are shifting for the first time from the United States to Europe due to concerns about attendees getting visas, organizers announced Monday.

Organized by the Annals of Improbable Research, a digital magazine that highlights research that makes people laugh and then think, the 36th annual ceremony will be held in Zurich. It’s usually held in the U.S. in September, a few weeks before the actual Nobel Prizes are announced.

“During the past year, it has become unsafe for our guests to visit the country,” Marc Abrahams, master of ceremonies and editor of the magazine, told The Associated Press in an email interview. “We cannot in good conscience ask the new winners, or the international journalists who cover the event, to travel to the USA this year.”

The move comes amid President Donald Trump’s sweeping crackdown on immigration, in which he has focused on deporting migrants illegally in the United States, as well as holders of student and visitor exchange visas.

Winners have for the past 35 years traveled to the United States to collect their prizes — and be showered with paper airplanes. Last year, winners included a team of researchers from Japan studying whether painting cows with zebralike stripes would prevent flies from biting them. Another group from Africa and Europe pondered the types of pizza that lizards preferred to eat.

The year’s winners, honored in 10 categories, also include a group from Europe that found drinking alcohol sometimes improves a person’s ability to speak a foreign language and a researcher who studied fingernail growth for decades.

But four of the 10 winners last year chose not to travel to Boston for the ceremony. In previous years, the ceremony has taken place at Harvard University, Massachusetts Institute of Technology and Boston University.

This year’s ceremony is being produced in collaboration with institutions of the ETH Domain, a domain of the Swiss Federal Institute of Technology, and the University of Zurich, Abrahams said.

“Switzerland has nurtured many unexpected good things — Albert Einstein’s physics, the world economy, and the cuckoo clock leap to mind — and is again helping the world appreciate improbable people and ideas,” he said.

Milo Puhan, epidemiologist at the University of Zurich and Swiss Ig Nobel Prize winner in 2017, welcomed the ceremony. “The Ig Nobel Prize makes research visible, and does so with a wink,” said Puhan, whose research ”showed that playing the didgeridoo trains the muscles and structures that keep the upper airways open, thereby reducing nighttime snoring and the severity of sleep apnea syndrome.”

Abrahams said the ceremony will be held in Zurich every other year. In between, the ceremony will shift to other European cities.

There are no immediate plans to return the ceremony to the United States.