Jigsaw puzzles are a great way to pass the time while also exercising your brain muscle. After a while, you begin to develop strategies like organising by border pieces, arranging stacks by colour, or focusing on one specific area and building out from there. And if you consider yourself somewhat of a puzzle master, sit tight, because we've rounded up some puzzles that make even expert-level ones seem easy. These puzzles include different themes but have one thing in common: their level of difficulty is very, very high. While a puzzle with fewer than 150 pieces doesn't sound too daunting, what if every piece was clear? Or what about a 1,000-piece puzzle with a multitude of colours — or lack of colours! — and you've got yourself a challenge. Keep reading to shop 11 mind-boggling puzzles for those looking for a serious challenge. Good luck!