  The Cosmic-Ray Extremely Distributed Observatory (CREDO) is a project
dedicated to global studies of extremely extended cosmic-ray phenomena, the
cosmic-ray ensembles (CRE), beyond the capabilities of existing detectors and
observatories. Up to date cosmic-ray research has been focused on detecting
single air showers, while the search for ensembles of cosmic-rays, which may
spread over a significant fraction of the Earth, is a scientific terra
incognita. The key idea of CREDO is to combine existing cosmic-ray detectors
(large professional arrays, educational instruments, individual detectors, such
as smartphones, etc.) into a worldwide network, thus enabling a global
analysis. The second goal of CREDO involves a large number of participants
(citizen science!), assuring the geographical spread of the detectors and
managing manpower necessary to deal with vast amount of data to search for
evidence for cosmic-ray ensembles. In this paper the status and perspectives of
the project are presented.
