song was included on Sandra's first greatest hits compilation, Ten on One (The Singles). Sandra and Michael Cretu married in January 1988 and moved to the Spanish island of Ibiza to work on what would be Sandra's third studio album. Into a Secret Land moved from electro-pop to more sophisticated areas of pop, showcased by the first single, "Heaven Can Wait". The second single, "Secret Land", met with even greater success, is considered one of her biggest solo hits while "We'll Be Together", released as the third single, was the first song she co-wrote. In order to promote her music in the English-speaking world, another compilation was released at the end of 1988, Everlasting Love. The album failed to enter the charts in the USA or the UK but a PWL remix of the title track included on the album charted at number 45 in the UK. 1989 saw the release of the final single from Into a Secret Land, "Around My Heart", which became another chart hit. With animal rights and nature conservation high on her personal agenda, Sandra took part in recording "Yes We Can" with 15 other performers for Artists United for Nature. Sandra's fourth album, Paintings in Yellow, was released in March 1990 and became her highest-charting album in her home country. "Hiroshima" was released as the lead single and was a hit. Danceable "(Life May Be) A Big Insanity" and ballad "One More Night" were released as the second and third singles off the album, respectively, but were only modest successes. Sandra accepted an award for the best-selling German artist at the 1990 World Music Awards in Monte Carlo. Also in 1990, the singer contributed vocals to four songs for her husband's musical project Enigma, including the worldwide number 1 hit "Sadness (Part I)". In early 1992, Sandra's fifth album was released, Close to Seven, which continued a more mature, less dance-orientated musical style. The album was a remarkable international success as was its lead single, "Don't Be Aggressive". However, the second single, "I Need Love", was her first since 1984 to fail to chart. Later in 1992, a new compilation was released, 18 Greatest Hits. It included most of her previous single songs and a re-recording of "Johnny Wanna Live", originally from Paintings in Yellow, which was released as a single and became a minor hit in Germany and the Netherlands. 1993–2006: Comeback attempts