Alternate flags of the continents:
Africa
The black and white represent (among other dualities) the sunny desert and the dense jungle, the light-skinned North Africans and the dark-skinned sub-Saharan Africans. The three suns represent the great sub-Saharan empires (Kush, Aksum, and Mali) as well as the great North African ones (Egypt, Carthage, the Moors) and the mineral wealth (the Gold Coast and the South African goldfields).
Europe
The red represents the brightly colored hair of the earliest Europeans, the brown represents trade and influence with ancient migrants from the Middle East, the yellow represents trade and ties with peoples to the east, the white represents the resulting new "race" ("white people") as well as ancient wisdom (Christianity, Judaism, paganism, and humanism), and the blue represents the depths of the Mediterranean as well as the current color of the Council of Europe and the European Union.
Asia
Red and yellow are common colors in many Asian cultures, especially Chinese but also to some extent Hinduism and Buddhism (saffron, in particular). The central symbol evokes a yin-yang, a Christian cross, a Hindu/Buddhist chakra wheel, the Sikh khanda, and the Islamic crescent - the overall design is based on the flag of the Maldives. The centrality of the flag represents the majority of humanity that lives in Asia and its status as a center of most world religions.
The Americas
This flag can be interpreted as North America and South America facing each other across a Caribbean Sea lined with white sand beaches and dotted with islands (the star). It also combines the color schemes from the Bolivar flags with the left-oriented star and stripes of the US, the red outer band of Canada and Mexico, and the bright blue of many Central American flags as well as that of Argentina. It is also intended to be the a modern-looking flag, representing the late integration of the Americas into the world.
Oceania
The black and blue represent the deep ocean and its waves, while the green bars represent the islands that dot the ocean. The red color represents the earth of the Australian Outback and the outer border represents the historic isolation of Oceania from Asia, the Americas, Europe, and Africa.