The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a large-scale physics experiment aiming to directly detect gravitational waves. Cofounded in 1992 by Kip Thorne and Ronald Drever of Caltech and Rainer Weiss of MIT, LIGO is a joint project between scientists at MIT, Caltech, and many other colleges and universities. Scientists involved in the project and the analysis of the data for gravitational-wave astronomy are organised by the LIGO Scientific Collaboration which includes more than 900 scientists worldwide. LIGO is funded by the National Science Foundation (NSF), with important contributions from the UK Science and Technology Facilities Council, the Max Planck Society of Germany, and the Australian Research Council. By mid-September 2015 "the world's largest gravitational-wave facility" completed a 5-year US$200-million overhaul at a total cost of $620 million. LIGO is the largest and most ambitious project ever funded by the NSF.

Jani is a Latvian anniversary festival, which celebrates the summer solstice, the day when it has the shortest night and the longest day. Although the shortest night is usually on 21st or 22 June, the public holiday - Ligo Day and Jani Day is on 23rd and 24 June. The day before Jani was formerly known as Zalu diena, which is now known as Ligo Day.