A safety ring is seen on a boat, made with plastic bottles, in Nymburk, Czech Republic July 12, 2014. Jan Kara, a 22-year-old student, and Jakub Bures, a 22-year-old car mechanic, built the 10-metre (32.8-feet) long boat from 5000 plastic bottles strapped to a wooden frame. They and two other men plan to pedal from their hometown Nymburk down the river Elbe to Hamburg in Germany to draw attention to an increasing plastic pollution in Europe, they said. (Photo by Rene Volfik/Reuters)

Jakub Bures (L) and Jan Holan attach a plastic garden chair to a wooden frame as they build a boat in their yard in Nymburk July 1, 2014. (Photo by David W. Cerny/Reuters)

(L-R) Jakub Bures, Jan Kara and Jan Holan attach plastic garden chairs to a wooden frame as they build a boat in their yard in Nymburk July 1, 2014. (Photo by Rene Volfik/Reuters)

Jakub Bures' hand is seen in between plastic bottles in a garage in Nymburk April 3, 2014. (Photo by David W. Cerny/Reuters)

(L-R) Jan Holan, Jakub Bures and Jan Kara attach plastic garden chairs to a wooden frame as they build a boat in their yard in Nymburk July 1, 2014. (Photo by David W. Cerny/Reuters)

Jakub Bures (front) and Jan Kara arrange sealed plastic bottles into the shape of a boat in their garage in Nymburk April 3, 2014. (Photo by David W. Cerny/Reuters)

Jakub Bures (R) and Jan Kara tie plastic bottles as they build a boat in their garage in Nymburk April 3, 2014. (Photo by David W. Cerny/Reuters)

A wrench and strapped plastic bottles are seen in a yard in Nymburk July 1, 2014. (Photo by David W. Cerny/Reuters)

(L-R) Jan Kara, Jakub Bures, Jan Brand and Jan Holan pedal their boat, made with plastic bottles, on the Elbe river near Kostelec nad Labem July 15, 2014. (Photo by David W. Cerny/Reuters)

Jakub Bures, Jan Kara, Jan Brand and Jan Holan pedal their boat, made with plastic bottles, on the Elbe river in Nymburk July 12, 2014. (Photo by Rene Volfik/Reuters)

A man (L) fishes as Jan Kara, Jakub Bures, Jan Brand and Jan Holan pedal their boat, made with plastic bottles, on the Elbe river near Kostelec nad Labem July 15, 2014. (Photo by David W. Cerny/Reuters)

Jakub Bures (R) and Jan Kara pedal their boat, made with plastic bottles, on the Elbe river near Kostelec nad Labem July 15, 2014. (Photo by David W. Cerny/Reuters)

People wave as Jakub Bures, Jan Kara, Jan Brand and Jan Holan pedal their boat, made with plastic bottles, during an official launch on the Elbe river in Nymburk July 12, 2014. (Photo by Rene Volfik/Reuters)

Jan Kara (R) and Jan Holan pedal their boat, made with plastic bottles, on the Elbe river near Kostelec nad Labem July 15, 2014. (Photo by David W. Cerny/Reuters)

Jakub Bures (R) and Jan Holan are seen through a cabin window as they pedal their boat, made with plastic bottles, on the Elbe river near Kostelec nad Labem July 15, 2014. (Photo by David W. Cerny/Reuters)

A yacht passes by as Jan Kara (R) and Jan Brand pedal their boat, made with plastic bottles, on the Elbe river near Kostelec nad Labem July 15, 2014. (Photo by David W. Cerny/Reuters)

Jan Kara drinks water from a plastic bottle on his boat, made with plastic bottles, on the Elbe river near Kostelec nad Labem July 15, 2014. (Photo by David W. Cerny/Reuters)

Jan Kara, Jakub Bures, Jan Brand and Jan Holan sit on their boat, made with plastic bottles, as they wait in a lock chamber on the Elbe river near Kostelec nad Labem July 15, 2014. (Photo by David W. Cerny/Reuters)