<P> Ferdinand de Lesseps, the man behind the Suez Canal, started a Panama Canal Company in 1880 that went bankrupt in 1889 in a scandal . </P> <P> In 1902--4, the United States forced Colombia to grant independence to the department of the isthmus, bought the remaining assets of the Panama Canal Company, and finished the canal in 1914 . </P> <P> A significant body of water (referred to as the Central American Seaway) once separated the continents of North and South America, allowing the waters of the Pacific and Atlantic Oceans to mix freely . Beneath the surface, two plates of the Earth's crust were slowly colliding, forcing the Cocos Plate to slide under the Caribbean Plate . The pressure and heat caused by this collision led to the formation of underwater volcanoes, some of which grew large enough to form islands as early as 15 million years ago . Meanwhile, movement of the two tectonic plates was also pushing up the sea floor, eventually forcing some areas above sea level . </P> <P> Over time, massive amounts of sediment (sand, soil, and mud) from North and South America filled the gaps between the newly forming islands . Over millions of years, the sediment deposits added to the islands until the gaps were completely filled . By no later than 4.5 million years ago, an isthmus had formed between North and South America . However, in April 2015, an article in Science Magazine stated that zircon crystals in middle Miocene bedrock from northern Colombia indicated that by 10 million years ago, it is likely that instead of islands, a full isthmus between the North and South American continents had already likely formed where the Central American Seaway had been previously . </P>

When did the collision between north and south america take place