A fine telling of the incredible story of Teddy Roosevelt's exploration of the course of a mostly unknown 1000 mile-long tributary of the Amazon river in 1913 - 1914 when he was age 55. In addition to the usual accouterments, piranha, the candiru fish, and hostile cannibalistic Indians, at least three characters, the former President, Colonel Cândido Rondon, and the president's second son, Kermit, are interesting principal actors. The story is complemented by appropriate review of the natural history of the forest and the geology of the river basin.

Note that accounts of the effects of the candiru fish may be exaggerated:
https://www.decodedscience.org/candiru-a-dont-pee-in-the-water-horror-story-debunked/31635

My e-book edition has two maps in it that you might be able to read with a magnifying glass, but no photographs. But there is a nice public domain image here:
https://commons.wikimedia.org/wiki/File:River-doubt-team.jpg
that says that it is scanned from an edition of this book.

President Roosevelt's own account, Through the Brazilian Wilderness is available and well-reviewed on Goodreads.