The most famous local market in Nepal is located in Thamel at Asan Tole, a busy square where six streets converge. It sits on one of two historical trade routes linking India and Tibet that pass through Kathmandu, and dates back to 500-600 B.C.
What adds an extra layer of awesome to this place is that these aren't some ruins preserved for tourists. This place was a market 2600 years ago, and it continues to be a market today. Mindblowing.