Sa Llotja is a Commodity Exchange built in the 15C to plans drawn up by the Majorcan architect Guillem Sagrera. The building appears to be fortified but includes an open gallery like a covered way. The merlons and turrets are more decorative than defensive. Gothic windows with fine tracery soften the severity of the walls. The very elegant trading room has intersecting ribs decorated with ribs falling down six beautiful twisted columns.