The detection of Einstein’s gravitational waves relies on highly precise laser measurements of small length changes. The kilometer-size detectors of the international network (GEO600, LIGO, Virgo) are so sensitive that they are fundamentally limited by tiny quantum mechanical effects. These cause a background noise which overlaps with gravitational-wave signals. This noise is always present and can never be entirely removed. But one can change its properties – with a process called squeezing, to date only used routinely at GEO600 – such that it interferes less with the measurement. Now, GEO600 researchers have achieved better squeezing than ever. This opens new ways to improve the international detector network in the next observation runs and is a key step to third-generation detectors such as the Einstein Telescope.