Tourism is a major industry owing to the city's climate, its beaches, and numerous tourist attractions such as Balboa Park, Belmont amusement park, San Diego Zoo, San Diego Zoo Safari Park, and SeaWorld San Diego. San Diego's Spanish and Mexican heritage is reflected in the many historic sites across the city, such as Mission San Diego de Alcala and Old Town San Diego State Historic Park. Also, the local craft brewing industry attracts an increasing number of visitors for "beer tours" and the annual San Diego Beer Week in November; San Diego has been called "America's Craft Beer Capital."

What type of tours attract a large number of visitors to San Diego?