World's Most Difficult Jigsaw Puzzles

Would you be brave enough to attempt any of these?

A few days ago, I saw this puzzle on G+; It's called Alexander's Star.

See it in action here :D

It somehow reminded me of the awesome Doctor Who puzzle I'm interested in buying. It's the famous exploding T.A.R.D.I.S. picture by van Gogh. (according to the series)

Not really important, I just felt like sharing. It does seem like the yellow could become a bit of a challenge, but it shouldn't be too difficult. The "worst" puzzle I've ever tried to build was this one:

"Nah, it shouldn't be too impossible. I can read music, so I should be able to do this with ease."

Turns out I was wrong. After completing the border and the line down the middle, I ended up having to test and try every piece in every possible place. I started arranging the pieces according to shape, in an attempt to find the necessary pieces easier.

I gave up eventually. :/

Google results led me to this puzzle: A 13,200 piece puzzle of about 1.3m x 2.9m. I guess it's meant for those HD junkies. Upon further inspection I found this 32k piece puzzle!

Not the most interesting design, but at that size I don't think you're buying it for the its aesthetic value.

Now this following puzzle, The Krypt Jigsaw Puzzle, is one for the completely dedicated / bored people.

"The Krypt features no discernible image. The entire 27" x 20" puzzle is a single hue of silver. There is absolutely zero variation in color between pieces."

I don't even want to begin imagining how long that would take!

Last, but not least, there's this "beauty":

A while back (and by "a while" I mean "a few years"), there was some hype about the World's Most Impossible Puzzle (or something like that). The creators offered money to those who could solve it first. All the pieces were square-shaped, with different colours / shapes on each side. You only had to match all the sides, and use all the pieces to solve the puzzle. Of course this means that there's a near infinite amount of possible combinations to try, but (possibly) only one way to solve it. It also had no border. The only way to solve it would be trial, error, and luck, or the Brute-force search. The latter could be done manually (poor soul), or by a computer. I'm not sure, however, if using software would be considered cheating. Meh. Who cares.

Sadly, I was unable to find this puzzle, as I couldn't remember exactly what it was called. It puzzled me for a while, but then I surrendered. I wouldn't try to attempt any of these puzzles anyway (except for the Doctor Who one).

Would you?