How can I properly create a large terrain?

Questions & Answers
1

How can I stitch terrains together to form a larger terrain while still being able to raise/lower the terrain height without gaps? I have tried setNeighbors, on each terrain tile, but this does not work. Using Unity 5.

2

Note that it is not enough to call this function on one Terrain, you need to set the neighbors of each terrain.
You sure you ant forgot this part? ^^
(talking about Terrain.SetNeighbors)

3

Can anyone answer this?