So, this is just a method on easily creating a cobblestone skyscraper without you having to put much effort into it (as long as you're in creative mode, not that it's impossible in survival; just difficult). I'm sure there are easier methods than this, but this one is really cool. It's especially cool to watch happen and how it works is pretty cool too. It's just cool, okay? 

*As a note, I would have pictures in this tutorial, but either my computer is being ridiculous or I just can't figure it out.

1. Before you start the actual construction, make sure you have a lava bucket, a water bucket, and cobblestone in your inventory. This is one reason why doing this in survival would be more challenging; you'd need more materials to stack up so you can reach, you'd need a lot of lava, and you'd need a lot of water.
   
2. For the real first step here, stack cobblestone up until you've reached the desired height of your skyscraper. Get rid of all but the top block.
   
3. Still using the cobblestone, build off of the lone block in the sky to form the square or rectangle shape that you want your skyscraper to be. This is like setting up the outline on the ground, except in the sky.
   
4. Using the lava bucket, tap each block on the side until you have lava flowing down on all sides. It will look like a lava skyscraper. Only put lava on the outside of your foundation, not the inside. It won't work if you put lava on the inside.
   
   
5. Wait for the lava to reach the ground on all sides.
   
   
6. Now using the water bucket, tap the top of each block until water is flowing down both the inside and the outside, covering every bit of lava. There will be a lot of sizzling noises. 
   
7. Wait for the water to cover all of the lava.
   
8. Place more cobblestone (or, if you're in survival, whatever blocks you can get a hold of) along the top on the very edge to get rid of the water on that side.
   
9. To get rid of the water on the inside, just do this same thing on the very inside part.
   
10. If there's any pools of water left up on the top, just cover it up or scoop it out. You can break blocks that are unnecessary. 
    

And that's a way to construct a skyscraper in Minecraft without too much effort by you. :)