The architecture of Glavni trg, where rich merchants' houses used to stand, proclaims the long-standing economic strength of the town. On the upper, commercial part of the square a special type of merchant - tradesman building with ground floor stone arcades was created. Round or segmental arches are supported on stone pillars, forming a vaulted arcade which served as the opening of a shop toward the street; the back of the shop was closed off by a recessed wall reaching into the passage. The pillars come in a variety of shapes: octagonal, square prismatic with slightly rounded corners, even some with spiral grooves. This distinctive shape has marked the square, which is one of the most beautiful in the country, since the second half of the 16th century. As to the construction of residential buildings, there are two main types of architecture. The poorer residential buildings were pushed to the perimeter of the medieval town, squeezed against the town walls or situated on top of them, consisting of living quarters only and no outbuildings. More impressive architecture especially characterizes the main communication route from the Gorenja (Ljubljanska) gate via Great (nowadays Main) Square to Dolenja (Karlovška) gate. Here the main residential building was built across the foremost part of an oblong lot, with a passageway through the ground floor providing access for foot and cart traffic into the courtyard, which was flanked on both sides by outbuildings. In some cases an outbuilding was constructed also across the furthermost part of the plot, thus creating a closed inner courtyard, not infrequently adorned with an arcade.