At the time of the novel's publication in 1899, the North Pole had still to be reached; it is little wonder the glamour was off for Marlow as up to that point all attempts on it had ended in failure, sometimes in death.
Though the location of the North Pole had been identified as early as the 16th century, it was not until the 19th century that expeditions set out with the explicit intention of reaching it. One of the earliest attempts was led by the British Naval Officer William Edward Parry, who in 1827 reached latitude 82°45′ North. In April 1895 the Norwegian explorers Fridtjof Nansen and Fredrik Hjalmar Johansen reached latitude 86°14′ North. On April 25, 1900, Umberto Cagni of the Italian Royal Navy reached latitude 86° 34’, beating Nansen's record by 35-40 km (22-25 miles).
The conquest of the North Pole was finally credited to US Navy engineer Robert Peary, who claimed to have reached the Pole on April 6, 1909, accompanied by Matthew Henson and four Inuit men. However, Peary's claim remains controversial.