Built near Portsmouth Square, the historic heart of San Francisco, Chinatown is the oldest and one of the largest in the United States. The entrance to Chinatown at Grant Avenue and Bush Street is called the "Dragon's Gate." Inside are 24 blocks of hustle and bustle, most of it taking place along Grant, the oldest street in San Francisco. This city within a city is best explored on foot; exotic shops, food markets, temples and small museums comprise its boundaries. Visitors can buy herbal remedies, enjoy samples at a tea bar or order a "dim sum" lunch. The former central telephone exchange of the Pacific Telephone and Telegraph Company stands at 743 Washington St. Now a bank, it is the first Chinese-style building constructed in San Francisco, and the exact site where California's first newspaper was printed.