Sentence:  Goodbye. I am going to the great grey-green, greasy <WSD>Limpopo</WSD> River, all set about with fever-trees, to find out what the Crocodile has for dinner. 
Meaning of the word marked with <WSD> tags:  A river of Africa that rises near Johannesburg and flows about 1,770 km (1,100 miles) to the Indian Ocean in Mozambique.