The Berlin Conference began on November 15, 1884 and ran until the following February, and essentially divided Africa into spheres of influence among major nations. Competition over the colonization of Africa was intense, and German Chancellor Bismark engineered the meeting to cut back on the conflicts among modern powers over exploitation of the continent. Fourteen nations were represented; Austria-Hungary, Belgium, Denmark, Great Britain, France, Portugal, Germany, Italy, the Netherlands, the US, Russia, Spain, Turkey and Sweden-Norway (united at the time). No Africans were invited or represented in any way.
About 80% of the continent was then still under local control, although the slaving expeditions of Arabs were in the process of almost denuding large areas of East and Central Africa of population. The map of Africa was divided up by the conference with no regard to the approximately 1,000 indigenous cultures. The boundaries of modern African states are largely the same as the colonial demarcations of the conference. Basically the French ended up dominating West Africa, the British Southern and Eastern Africa. The Germans held four colonies geographically spread out, Portugal two in the south and one in the west, while Belgium owned the huge swath in the middle of the continent called the Belgian Congo, today both the Republic of Congo and the Democratic Republic of the Congo (yesterday's Zaire).
There was good which came from the conference, largely the effort to curtail the slave trade and the opening up to the modern world of the vast interior of Africa. The exploitation of Africa brought investment in infrastructure, the building of towns and cities, etc. Unfortunately, the European powers ran their colonies in a variety of ways, from the British allowing local governments to largely continue to the outright ownership of the Congo and its people by King Leopold II of Belgium. Some colonies were run fairly benignly, others more brutally. The Europeans in general were ignorant of the cultures and aspirations of native peoples, and remained that way for the most part. Colonial exploitation has had its drawbacks throughout history, and this probably has been demonstrated more in Africa than anywhere else. Even in those colonies run in more paternalist manners, the local population was never invited to share power in ways which could have taught them modern self-government, an ommision made all too clear by many African governments following decolonisation post World War II.
The worst effect was the boundary lines. Drawn to establish borders for the interests of mining and other industries,they had (and have today) no relationship to tribal boundaries, culture or language, and this has left a legacy of internal conflict in African nations to this day.