Rebels, called the M23, have taken Goma, the main city of North Kivu, one of the Democratic Republic of Congo (DRC)'s eastern provinces. Their plan is to march to Bukavu, the main city of South Kivu, and from there, they say, across the massive country to Kinshasa, the Congo's capital.
A geographical note is in order. The DRC's principal cities are part of greater urban areas that cross international borders. Look at the capital, Kinshasa, on a map, and you will see Brazzaville, the capital of the other Congo, right next to it.