San Francisco's first and oldest sister city officially cut its ties with the Bay Area this week.

The split between Osaka, Japan, and San Francisco was initiated by Osaka Mayor Hirofumi Yoshimura. The dispute between the two cities began in 2015 over the Comfort Women Memorial in San Francisco's Chinatown. "Comfort women" were women and girls forced into sexual slavery by the Japanese military during World War II.

The memorial features the statues of three women standing up and holding hands, one from China, one from Korea and one from the Philippines -- three countries where many "comfort women" were from. The statue is accompanied by educational tools that teach about the dark history of "comfort women."