It’s said more than once in the true-life adventure “The Lost City of Z” that a man’s reach should exceed his grasp. The motto applies to the heroic lead character, Percy Fawcett (Charlie Hunnam), who repeatedly left a life of comfort to find his life’s meaning in dangerous circumstances.

As an explorer of the remarkably perilous jungles of early-20th-century South America, home to snakes, cannibals and headhunters, and as a British Army officer on the front lines in France in World War I, Fawcett was a learned gentleman, a fearless daredevil and a maverick. He entered unmapped lands far from the British Empire not as a conqueror but a visitor, treating those he encountered as a guest in their land, and seeking to return with nothing more than new understanding.

The reach-exceeding-grasp maxim also relates to the creativity captured by James Gray, the writer/director of this beautifully detailed film. Gray shows that he can create a world that looks historic yet feels significant a century later. For someone whose films until recently been modern and emotional rather than epic, this is one heck of a stretch.

And a successful one. He turned that corner three years ago with “The Immigrant,” an operatic drama of New York’s Lower East Side in 1921. This one goes even further in terms of its scope and ambition, with travels on rivers and through jungles that are a series of extravagant tableaux. The moody cinematography by Darius Khondji (“Se7en”) is a master class in sumptuously composed wide-angle compositions.

Following its audacious leader ever deeper into jungle mysteries, the film keeps a cool head and a compassionate stance about all the native strangers and distant lands it visits. Gray is making the type of intelligent movies that no major studio will currently invest in. It’s their artistic loss and our gain as Amazon and other streaming services step in to fill the gap.

Based on David Grann’s nonfiction bestseller, the film crams as much information as possible into its 141-minute running time. It balances insights into Victorian standards of honor and duty with a grip on contemporary attitudes about the era’s assertive colonialism. Hunnam plays Fawcett as a man of formidable courage and humility. He was a member of the United Kingdom’s establishment, but never a comfortable part of it. When he was approached by the Royal Geographic Society to lead an expedition to chart part of the frontier between Bolivia and Brazil, he accepted it as his honorable obligation.

He left his family at length, returning even after one trek became a debacle marked by a witless patron. In a movie full of good things and talented people, Angus Macfadyen is a dreadful wonder as the ignorant, petty, slightly mad would-be commander of the voyage. Contrasting the characters, Gray is as insightful a political moralist as he is a cinematic stylist.

Gray also digs into the troubled relationships that Fawcett’s relentless exploration created with his wife (Sienna Miller) and his eldest son (Tom Holland, the new Spider-Man). The excellent performances include a fine supporting role from an entirely different Robert Pattinson as Fawcett’s army buddy and fellow adventurer.