Still, the album enjoyed commercial success. Houston became the first woman in music history to debut at number one on the Billboard 200 albums chart and the first artist to enter the albums chart at number one in both the US and UK, while also hitting number one or top ten in dozens of other countries around the world. The album's first single, "I Wanna Dance with Somebody (Who Loves Me)", was also a massive hit worldwide, peaking at number one on the Billboard Hot 100 and topping the singles chart in 17 countries, including Australia, Germany and the UK. Her next three singles, "Didn't We Almost Have It All", "So Emotional" and "Where Do Broken Hearts Go", all peaked at number one on the US pop chart, giving Houston a record total of seven consecutive number one hits; the previous record of six consecutive number one hits had been shared by the Beatles and the Bee Gees. Houston became the first woman to generate four number-one singles from one album. Whitney has been certified Diamond in the US for shipments of over ten million copies and has sold a total of 20 million copies worldwide. At the 30th Grammy Awards in 1988, Houston was nominated for three awards, including Album of the Year. She won her second Grammy for Best Female Pop Vocal Performance for "I Wanna Dance with Somebody (Who Loves Me)". Houston also won two American Music Awards in 1988 and 1989, respectively and a Soul Train Music Award. Following the release of the album, Houston embarked on the Moment of Truth World Tour, which was one of the ten highest-grossing concert tours of 1987 and the highest-grossing tour by a female artist, topping tours by both Madonna and Tina Turner. The success of the tours during 1986–87 and her two studio albums ranked Houston No. 8 for the highest-earning entertainers list according to Forbes. She was the highest-earning African-American woman overall, highest-earning musician and the third highest entertainer after Bill Cosby and Eddie Murphy. Houston was a supporter of Nelson Mandela and the anti-apartheid movement. During her modeling days, she refused to work with agencies who did business with the then-apartheid South Africa. On June 11, 1988, during the European leg of her tour, Houston joined other musicians to perform a set at Wembley Stadium in London to celebrate a then-imprisoned Nelson Mandela's 70th birthday. Over