In a manner similar to Los Angeles, Bangkok is transforming into a region where traffic flows in all directions rather than simply to the central core, as it once did. Suburbanziation has swallowed ever more fields and swamps, though even parts of Bangkok itself are not built-up. The first areas to suburbanize were in Pathum Thani, Nonthaburi, and Samut Prakan Provinces. Other areas more recently have agglomerated in Samut Sakhon and Nakhon Pathom. Samut Prakan, Nonthaburi, Pathum Thani and Samut Sakhon all have historic city centers.