Enya's 1988 recording Watermark achieved landmark success with her groundbreaking use of multi-tracking technology to fuse new age and Celtic themes and instrumentation. The meticulous production defines her sound and achieves continuity even while weaving together tender ballads, piano pieces, massively layered vocal harmonies, and symphonic synthesizer movements. Although Enya's pristine voice isn't especially strong, her lead vocals possess a vulnerability that reflects the lyrics' sense of personal searching. From the ubiquitous, frothy single "Orinoco Flow" (which was used to hawk Crystalmore… Light on TV) to the hard, bold edge of "Cursum Perficio," Enya's style remains fresh and engaging today.