The seven centuries old, 40 feet high mud wall that goes around the old city is also quite well-preserved, and is a sight in itself. It contains the Bab-al-Yemen, a large portal that celebrates the entrance into the old city. Out of the original six gates that marked the entry into Sana'a, it is the only one surviving in its original shape. Slip into a time warp as you pass through the large gate, being sucked into a busy marketplace that has existed at the very same place for centuries. You can go up to the top of the gate for some splendid views around the marketplace below, and the old town beyond. As trading activities cease around late evening, soft, hazy illumination lights up the gate, adding a visually alluring touch of magic to it.