Another old and important site in the city is the Shah Abbasi Caravanserai that now houses the Zilu Museum. The Zilu Museum is dedicated to the hand-looming of prayer rugs. It is the first and only museum of its kind. Some fine examples date back to the 16th century although this craft dates back to the Sassanid dynasty. It is possible to see how they are made in the workshops occupying some of the former caravanserai lodgings. The cotton kilims are double-sided and many feature the cypress tree. Only a dozen zilu masters still work at this ancient craft.
Zilu is more appropriate for hot regions, especially on the borders of the desert, as it is made entirely of cotton. It seems, however, that Zilu weaving is at a more developed stage than Kilim. Zilu mainly uses geometric patterns, and sometimes the designs take the form of inscribed tablets.
Contrary to other Iranian carpet types, Zilu has a limited variety of colours. The colours which are used, like those in other regions, were locally produced. Generally, Zilu is categorized into three types based on colour and function. White and blue ones are mainly used in mosques and holy places. The red and blue ones are used inside houses, while green and red ones are of the highest quality.