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In 1885 , he first went to Africa , participating in a German scientific expedition to Nigeria and travelled in the western Sudan ( 1885 ) , and in South-West Africa , now Namibia ( May 1888 to January 1889 ) , mostly in the western mountains from Otjitambi to Rehoboth , to do geological research on behalf of the " Southwest African Gold Syndicate " ( Südwestafrikanisches Goldsyndikat ) , with the aim of exploring alleged deposits of gold .
 Nigeria, Namibia
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Nigeria, Namibia