[mecameron]

The surface of the Earth is finite in size and has no edges. You can keep progressing forward without hitting an edge.

[Neeek]

There have been recent studies which show that universe is probably "flat" though.

[cygx]

Or very slightly curved - measurements come with error bars, so we can't be sure if it's exactly flat. Also note that flatness and finite size are compatible in case of non-trivial topology (think of the flat torus - pacman world - which, however, is not isotropic).