King Solomon's Mines & Allan Quatermain by H.Rider Haggard

In King Soloman's Mines, Sir Henry Curtis and Captain Good persuade Allan Quatermain to help them find Sir Henry's brother George, who has gone missing in the unexplored African interior while searching for the legendary treasure trove of a lost kingdom. Quatermain agrees to lead the expedition, though he has little hope they will return alive.
 
A hazardous canoe journey along an underground river leads them to Zu-Vendi, a land ruled by two beautiful queens. Both queens fall in love with Sir Henry and the explosive situation leads to civil war, several battles, many funerals and a wedding.