We boarded our bus, and in order to get into Phnom Penh, we actually had to board a ferry to cross the Mekong River. This really struck me as a clear indication of the relative poverty of Cambodia compared to Vietnam. In Vietnam's big cities that sit on rivers, there were numerous bridges. Phnom Penh is the largest city in Cambodia, but has no bridges to cross the biggest river it sits on the bank of. Imagine New York City with no Hudson crossings.