Constructed at the mouth of the Singapore River, the Fullerton Building was opened in 1928. It housed various government offices including the all-important General Post Office. The General Post Office was so important that it was the anchor tenant of the building and took up the basement, ground floor and the first floor. Mail was often delivered on carts by land or even by boat along the river and along the original coastlines of Singapore. From the 1800s to the 1970s, Singapore used mile stones as a point of reference for addresses. Fullerton Building is known as Mile 0, because this is where all the mail was sent away from at that time. You can find a circular plaque on the floor marking the Fullerton Building as Mile Zero on the exterior of the building.