Can you spot what's wrong with this apartment?

An unusual apartment has been rented out, but some applicants have noticed a glaring problem with the bathroom.

The tiny apartment has a very unique layout- the kitchen and bathroom are in the same place. The all-purpose space includes a toilet, bathtub, oven and sink all in one room.

The 18.5 square-metre apartment is in St. Louis in the US and has just been rented to a male applicant.

The advertisement and photo for the $731 per month apartment appeared on several websites and had people flushing with excitement.

The tiny St. Louis apartment has a unique layout
The tiny St. Louis apartment has a unique layout. Source: AP

The 111-year-old building originally housed 12 luxury apartments.

Harold Karabell of S.F. Shannon Real Estate Management says the new tenant loves it.

Mr Karabell says that around the time of the Great Depression, it was remade into 50 small units, this studio the smallest among them.

Toilet and kitchen combination aside, Mr Karabell says the apartment has a lot to like, including refinished hardwood floors and new windows.

– With AP