If you want to launch a rocket into space, as I’m sure practically all of you are at least contemplating, where should you do that? The main thing is of course to avoid populated areas, to limit the damage if the thing blows up. The launch pad itself should be located away from people, and there should be a large uninhabited region to the east of the launch site (an ocean is fine). Why to the east? Think about it, the answer follows below.
The main challenge of getting into orbit is not the height. If you fly straight up for 400 km (250 miles), you will simply fall down again. The main challenge is to accelerate enough to actually stay in orbit. For an orbit at 400 km, which is where the International Space Station (ISS) is, the necessary speed is about 28000 km/h (17000 miles/h). This is why there is huge difference in difficulty between getting to orbit and so-called sub-orbital flights, like those of SpaceShipOne. SpaceShipOne reaches a speed of about 3500 km/h (2200 miles/h), far too slow to stay up there. The trick to stay in orbit is to compensate for falling down by moving sideways just quickly enough to miss the Earth, which means that most of the acceleration of the rocket must be in a horizontal direction, not up. Hence the need for uninhabited space in a certain direction, not just in a region around the launch pad.
Another trick is to be close to the equator. Indeed, if you are “standing still” at the equator, you are actually moving east at more than 1600 km/h (1000 miles/h), due to the Earth’s rotation. This gives you some initial speed for free, if you launch towards the east, so that is where your ocean should be. This advantage decreases when you move away from the equator (since the surface of the Earth covers less distance in the same time at higher latitudes), so it is best to be as close to the equator as possible.
The main spaceport of the United States, Kennedy Space Center, seems to be in the best place that they have available on the mainland: the eastern coast of Florida. Russia had no such luck, and had to settle for a steppe region for the location of Baikonur (Байконур in Russian). Europe seems to have drawn the main prize here, since their spaceport in Kourou (French Guiana, which is an overseas region of France) is very close to the equator, with the Atlantic Ocean to the east, as in Florida. A completely different approach is to launch from the middle of the ocean, as Sea Launch does. Once you’ve decided to accept the extra hassle of a floating launch platform, you can put it at exactly the right spot, on the equator and far away from land.
So, you know what to do now!