Population growth is a serious problem. According to the World Health Organization (WHO), just 34 percent of the world's population lived in urban areas in 1960 — in 2014, the percentage had climbed to 54 percent. With growth expected to continue at rates above 1.5 percent between 2015 and 2025, it's likely that someday soon most of us will have the need for multiuse furniture. 

A piece of furniture that can double as an ottoman and a coffee table is infinitely more useful to someone starved for space than a piece that only accomplishes one of those goals. The Murphy bed was invented about 100 years ago, but transformable furniture has come a long way since then, as evidenced by this sofa from ProTeas, a furniture company based in Greece. 

Interestingly enough, it seems that when William Murphy made the bed, it wasn't out of concern for space. Around the turn of the 20th century, it wasn't proper for a lady to enter a man's bedroom, which caused problems for Murphy in his studio apartment, according to smithsonian.com. He reportedly devised the fold-up bed so that his apartment would feel like a parlor instead of a sleeping chamber. A century later, we're returning to Murphy-esque techniques, but for an entirely different reason. 

This is far from the only example of transformable furniture out there -- and far from the most interesting piece out there. This high-end French company offers luxury versions of a Murphy bed, but they come down from the ceiling, instead of from the wall. Unlike Murphy's contraption, these pieces of furniture seem aspirational — it's hard to imagine a living space, big or small, that wouldn't sparkle with the addition of one of their beds.

For folks with kids, a bunk bed might make a lot more sense. While Murphy bunk beds do exist, the sofa below is probably the next closest thing, and it's a bit less ridiculous. It would be a wonderful addition to any children's playroom, especially for when their friends stay over. Check out the clip below. Readers who enjoy it are encouraged to engage with us on our Facebook page, or in the comments underneath!