|The Kisinski brothers and friend on their "Amazon Bikes"|
They developed bikes that could be converted from road to river operation and back to road. These were tested them on the Warta River in Poland. Once ready, they road their bikes through Peru up into the Andes Mountain, before reaching the headwaters of the Amazon. They had a local guy (In the middle of the photo) make some modifications to the bikes for the faster flowing Amazon. The brothers started their adventure in September of 2015, and reached the Atlantic Ocean on March 4, 2016.
You can read more about the trip on their website. Keep in mind that English is not their first language, so their writing can be a bit difficult to understand at time. Also, I found their website a little challenging to navigate.