In 1992, as apartheid was finally crumbling, Sharon Katz and Nonhlanhla Wanda formed South Africa’s first multiracial, multilingual, multicultural choir.

In 1993, they did a nationwide tour of their homeland, by train, with 150 choir members, a 10-piece band and top South African a cappella group Ladysmith Black Mambazo.

Katz and Wanda are featured in the award-winning 2015 documentary, “When Voices Meet,” which screens — with free admission — Friday at Balboa Park’s WorldBeat Center.

The screening will be preceded Wednesday by Katz, Wanda and their five-member Peace Train Band’s Nelson Mandela Centenary concert, also at the WorldBeat Center. The band’s percussionist, Robert Felcher, is a San Diegan, while the other members hail from Philadelphia, Los Angeles and Berkeley.

Katz and Wanda plan to invite audience members who attend the Wednesday and Friday events at the World Beat Center to join them for next weekend’s Peace Train Transcending Barriers Project. Singers and supporters of all ages are invited to attend an initial, pre-event rehearsal, which is scheduled for 3 p.m. today, July 15, at the World Beat Center.

The Peace Train Transcending Barriers Project. is scheduled to start at 9 a.m. on Saturday, July 21, when Katz, Wanda, their band and about 100 volunteer singers rehearse at the World Beat Center.

At 10 a.m., they will march and sing in a parade from the World Beat Center past San Diego City College to the San Diego Trolley stop at 12th Avenue and C Street. They will then ride the trolley to San Ysidro and, with passports in hand, walk across into Mexico.

Once on on the Tijuana side of the border, they’ll meet and then join arms with Mexican participants from Promotora de las Bellas Artes. Together, they’ll engage in what Katz describes as a “solidarity parade” to the Tijuana Cultural Center (CECUT).

After arriving at CECUT, a multinational choir of South Africans, Americans and Mexicans — including a Tijuana children’s vocal group — will share a meal, hold workshops and rehearse together for the first time to prepare for their free evening concert of unity at CECUT.

After the 6 p.m. performance concludes, charter buses will take participants who traveled to Tijuana from San Diego back to the World Beat Center. Anyone who wishes to register in advance to participate in Saturday’s parade and concert, or make a donation to help underwrite the event, can do so by sending an email to: [email protected]

Sharon Katz & The Peace Train, featuring Nonhlanhla Wanda, “Transcending Barriers” San Diego concert and free film screening

When: 7 p.m. Wednesday Nelson Mandela Centenary concert; 7 p.m. Friday film screening of “When Voices Meet”; 7 p.m. Friday:

Where: Both events are at WorldBeat Center, 2100 Park Blvd., Balboa Park

Tickets: The film screening is free. Concert admission is a suggested $10 donation

Phone: (619) 230-1190

Online: eventbrite.com.

Sharon Katz & The Peace Train, featuring Nonhlanhla Wanda, “Transcending Barriers” Tijuana parade and free concert

When: Noon Saturday, July 21, unity parade begins at at the Tijuana side of the U.S./Mexican border and proceeds to the Tijuana Cultural Center (CECUT). afternoon workshops will be followed by a free 6 p.m. concert at CECUT.

Where: Tijuana Cultural Center (CECUT), Paseo de los Heroes No. 9350, Zona Urbana Rio, Tijuana.

Tickets: Admission is free

Phone: (215) 495-9562 or 011-526-64-290-0951.