Which word has an error in the sentence: San Francisco is one of the many cities in the world which have recently been hit by earthquakes?

The word "have" contains an error in this sentence due to the subject-verb agreement principle. The phrase "one of the many cities" indicates that "San Francisco" is being treated as a singular subject, despite being part of a larger group. Thus, the verb should correspond to that singular subject. Instead of "have," the correct verb form should be "has" to properly align with the singular subject. This allows the sentence to accurately convey that San Francisco, as a single city, is one member of the larger group affected by earthquakes.