Everyone wants a unique souvenir from their vacation, but trip tokens can land travelers into serious trouble if they are not carefully chosen. Taking sand or shells from beaches, for example, is a big no-no, especially on the Italian island of Sardinia.

One French couple probably (definitely) took it too far when they packed 90 pounds of sand from Chia Beach in Sardinia into 14 plastic bottles, claiming they wanted it as a souvenir. They were caught as they were about to board a ferry to Toulon, France. Now, they face up to six years in jail.

Since Sardinia’s white sand is considered a public good, it’s forbidden to remove it from the island. Attempting to bring it home is considered theft. The law, enacted in 2017 to protect the beautiful environment of the island, states that trade in sand, pebbles, and shells is illegal, and punishable by fines of up to $3,330.

As reported by The Guardian, this summer police have seen an increase in sand, shells, and other beach items found in people’s luggage at the island’s airports; ten tons were seized at Olbia, in the northwest of the island, in the past few weeks alone.