Not so hidden beneath the busy streets of Toronto is the PATH, a vast system of tunnels and building basements connecting subway stops, business towers, sports complexes, tourist attractions, shopping centers, hotels and governmental offices.

Walking the 17 miles of tiled, underground area can lead one from the train station to Toronto’s busiest attraction (the Eaton Centre) to the city’s Ritz-Carlton Hotel to the Hockey Hall of Fame to a hockey game, all without stepping outdoors.

The size and number of businesses included in the structure has led Guinness World Records to declare it the largest underground shopping complex in the world. With 4 million square feet of space for retailers, the mall is comparable to the West Edmonton Mall, the largest mall in in North America, though it’s not classified the same way (Eaton Centre is the fourth largest mall in Canada on its own). It’s more akin to the modern underground “cities” of the world in Montreal or across Japan. It also holds the record for largest underground ‘sidewalk’ sale, held annually.

Toronto’s most iconic landmark, the CN Tower, is also connected via a raised, enclosed sidewalk from the city’s central train station (Union Station). The Toronto Blue Jays home field, Rogers Centre is also part of this.

The complex is busy enough to warrant maps and apps for daily users to follow sales. It’s also color coded to help with navigation. The letters P A T H represent the cardinal directions, starting with south and moving clockwise. Therefore P is South, A is West, T is North and East is H. This may seem confusing, but when you are navigating an underground city, any direction is helpful.