Columbia subject headings:
Humboldt, Alexander von, 1769-1859--Travel--Mexico.
Humboldt, Alexander von, 1769-1859--Travel--South America.
Mexico--Description and travel.
Scientific expeditions--Mexico.
Scientific expeditions--South America.
South America--Description and travel.
Harvard subject headings:
Humboldt, Alexander von, 1769-1859.
Latin America--Description and travel.
Natural history--Andes Region.
Natural history--Mexico
Princeton subject headings:
Humboldt, Alexander von, 1769-1859--Travel--Mexico.
Humboldt, Alexander von, 1769-1859--Travel--South America.
Mexico--Description and travel.
Scientific expeditions--Mexico.
Scientific expeditions--South America.
South America--Description and travel.