The 2001 CIA World Factbook

by United States. Central Intelligence Agency

Guatemala: lowest point: Pacific Ocean 0 m

highest point: Volcan Tajumulco 4,211 m

Guernsey: lowest point: Atlantic Ocean 0 m

highest point: unnamed location on Sark 114 m

Guinea: lowest point: Atlantic Ocean 0 m

highest point: Mont Nimba 1,752 m

Guinea-Bissau:
lowest point: Atlantic Ocean 0 m

highest point: unnamed location in the northeast corner of the
country 300 m

Guyana:
lowest point: Atlantic Ocean 0 m

highest point: Mount Roraima 2,835 m