Made famous by the film, City of Ghosts, Post Office Square is one of the last places in Phnom Penh to glimpse the slow-paced, pot-holed city of old. A short detour from riverside and Wat Phnom, the area deserves a visit in its own right.
The post office was built in 1890, then eventually restored and fully reopened in 2004. It fronts a small square on Street 13 — really it’s just a widening of the road — and is surrounded by other examples of colonial architecture in various states of upkeep. The post office is open 07:30 to 17:00, with a healthy two-hour lunch break from noon. Stamp collectors can make impulse purchases at the philatelic counter. source: http://www.travelfish.org