[The hardest thing about '90 Millas' was the concept of] combining the old and the new without losing the authenticity. The simple solution, of course, would have been to record covers. [But] emotionally it wouldn't have been the same We left Cuba as children: Gloria was 1, I was 14. So, there ia a part that does exist in nostalgia, but a the same [time] there is another part that is contemporary music that we've made all over the world.