Belize City is the largest city in the country and its main transport hub, sitting where the Belize River meets the Caribbean Sea. Most international flights land here, and the water taxi and bus terminals are the departure points for the cayes and the interior.
Many travelers pass through quickly, and that's a reasonable choice — there's not an enormous amount to do. But the city has a rawer, more authentic energy than the tourist-polished cayes. The old colonial architecture along the waterfront, the Museum of Belize (housed in a former colonial jail), and the Swing Bridge — still operated manually and swung twice daily for boat traffic — are worth an hour or two.
Crime is a real concern, particularly in the Southside. In tourist areas (the Fort George neighborhood, the waterfront) it's generally fine, but take taxis at night and don't flash valuables. The city's problems are concentrated in specific neighborhoods that tourists have no reason to visit.
The Fort George area, north of the Swing Bridge, has most of the better hotels and restaurants. The Marine Parade waterfront is a pleasant stretch for a walk, with the Fort George Lighthouse and the Baron Bliss Memorial at its northern tip. The story behind Baron Bliss — an English nobleman who left his entire estate to Belize despite never setting foot on shore — is one of the stranger tales in the country's history. The House of Culture, the former colonial governor's residence, and St. John's Cathedral, the oldest Anglican church in Central America, round out the main sights. The Marine Terminal for water taxis is on North Front Street.