LIGO-Virgo-KAGRA 

The advanced LIGO-Virgo-KAGRA (LVK) gravitational waves detector network consists of the two LIGO interferometers, located in the US in Livingstone and Hanford, the Advanced Virgo interferometer, located in Italy in Cascina and the KAGRA interferometer, located in Japan in the Kamioka mountain.

The image below shows the LVK network and the respective location together with the GEO600 detector, another detector that however is limited in sensitivity.

This global network of gravitational wave detectors works together to observe and analyze data originating from "ripples" in the structure of the  spacetime caused by cataclysmic cosmic events, such as black holes and neutron stars mergers. By combining data from multiple detectors, the LVK collaboration can pinpoint the sources of these events more accurately and study their properties with great details detail and a level of accuracy that exceed those of the individual detectors. The inclusion of detectors in different parts of the world allows for improved sensitivity and coverage, enhancing the ability to detect and localize gravitational waves. 

• LIGO (Livingston and Hanford): Operating since 2002, these twin detectors in the US have been at the forefront of gravitational wave detection, making the first direct observation of gravitational waves in 2015. Their primary feature is their long 4 km arms, which allow them to detect minute changes in spacetime with high precision.
• Advanced Virgo (Cascina, Italy): In operation since 2007 (with significant upgrades completed by 2017), Virgo features 3 km long arms and works in collaboration with LIGO. Its main strength is its sensitivity to low-frequency gravitational waves, improving the network's ability to detect a broader range of events and their sky localization.
• KAGRA (Kamioka, Japan): The newest of the interferometers, KAGRA has been operational since 2020. It is unique as it is the first underground interferometer and uses cryogenic cooling to reduce noise, making it highly sensitive to gravitational waves, particularly those from low-frequency sources.

Together, this global network enhances the ability to detect gravitational waves, offering precise localisation and improving the overall sensitivity to a wide range of cosmic events.