Where can i get good Heightmaps to use?

Is there anywhere i can download Heightmaps to use in Lumberyard? All the ones i am finding seem to come out awfully spikey or blocky when i import them? Or am i missing something?

Try lowering the Max Height variable in the terrain editor. Go to Terrain Editor–>Modify–>Set Terrain Max Height. I usually have to lower it down to around 512 or 256 for my terrains.