For a lunar eclipse, everyone on the dark half of the earth can see it... just look at the Moon, and see the Earth's shadow (which is big) move across it! But for a lunar eclipse, the Moon's shadow on the Earth is very small and travels quickly, so you have to be in exactly the right place and exactly the right time, in order to see the Corona. But it's worth it! I've now been on the center line of a total eclipse ten times and have only been clouded out once, but I've had a couple of near misses...
Here's one of my favorite eclipse photos that I took in China in 2008
http://space.rice.edu/eclipse/solar_eclipse_2008/eclipse_REIFF2909s.jpg