Conversation so far:
What did Thomas Nast do after leaving Harper's Weekly?
In 1890, Thomas Nast published Thomas Nast's Christmas Drawings for the Human Race.
Which newpapers did Thomas Nast work for?
In 1892, Thomas Nast took control of a failing magazine, the New York Gazette, and renamed it Nast's Weekly.
Where did Thomas Nast work after Nast's Weekly?
President Theodore Roosevelt was an admirer of the artist and offered Thomas Nast an appointment as the United States' Consul General to Guayaquil, Ecuador in South America.
How did Thomas Nast support his family after leaving Harper's Weekly?
In need of income, Thomas Nast returned to the lecture circuit in 1884 and 1887.
Are there any other interesting aspects about the Thomas Nast article besides everything mentioned previously?
During a subsequent yellow fever outbreak, Thomas Nast remained on the job, helping numerous diplomatic missions and businesses escape the contagion.
Did Thomas Nast die from Yellow fever?
Thomas Nast contracted the disease and died on December 7, 1902.

Question: What was his most famous accomplishment after leaving Harper's Weekly?
Self-contained rewrite: What was Thomas Nast's most famous accomplishment after leaving Harper's Weekly?