The director of the Auschwitz Memorial in Poland has offered to serve part of the 10-year jail sentence given to a 13-year-old Nigerian boy for blasphemy.
Dr Piotr Cywinski said he and another 119 volunteers from all over the world would each serve a month in prison.
He personally asked Nigerian President Muhammadu Buhari to pardon the boy.
The boy was convicted by an Islamic court of making uncomplimentary remarks about God during an argument with a friend in Kano state in August.
The boy’s lawyer later appealed against the sentence, saying it violated children’s rights and Nigeria’s constitution. He told the BBC that no date had been set for the appeal to be heard in court.
Kano is one of 12 Nigerian states practising the Sharia legal system alongside the country’s secular laws.
Muslims form the majority in the north of the country.