Mojang & Microsoft has included a bunch of strange and cool new features with each new update and snapshot,but did you hear/see about the structure block?
STORY--- I was working on another one of my easy parkour/puzzle maps called Softcore Parkour 2 and I'm trying to use the fill command to place a bunch of string down(/fill [some numbers xyzxyz dat stuff] minecraft:str  )and a press TAB with this command and one of the options was a block called a Structure Block.Some of you may heard about it,others may have not.Looking at this new block I discovered,I remember in a YouTube video about secret 1.9 features by SwimmingBird941 it was revealed it is a block used for generating structures in-game.Some other stuff I found about with this crazy block is that you can't press Button 3 on your mouse and get it into your inventory in creative mode.It's also an unbreakable block(if you're in survival, that is).With it's S,I think it can be helpful for maps or text.Or for adding a new block into Minecraft with Vinilla Mods!Also,another weird thing I found out is if you look to the right of the picture,you can see under the  minecraft:structure_block part it says Mode:SAVE .This means nothing to me,but if you can figure it out,okease let me know in the comments below.
GETTING THE BLOCK---I tried to use /give to get the block into my inventory,which didn't work.The only way I figured out how to place this awesome block into your world is using the /setblock command or using /fill. EXAMPLE---  /setblock ~ ~ ~ minecraft:structure_block

If you find out any other cool new features about this structure block, please let me know!