The Registan Square in Samarkand is commonly known as the 'jewel in Central Asia's crown'. It is well worth visiting. Entry costs just a few dollars (5000Uz Som) but visitors should be aware that they are also required to pay (not much) for a licence to take pictures. Overly officious Uzbekistan camera 'police' will ask you to show your 'licence'. That said, however, it is indeed a spectacular monument to 14-16th century Islamic culture and architecture. The mosaic work is stunning, and a local guide whould provide you with with interesting information about its history for a nominal fee. Local artisans inhabit former prayer rooms and provide interesting insight into silk making, carpet making, Uzbekistan musical instruments and pottery. The local traders put no pressure on to buy any souvenirs and it was enjoyable haggling for a few less dollars (or sum) as expected. The Registan was one of the highlights  of Uzbekistan. If you get the opportunity to go there, the locals will smother you with kindness!