In the last decade, an exponential growth in the number of smart objects is observed. These devices, designed to enhance the human well-being, are able to communicate and cooperate with each other to form the IoT (Internet of Things). However, the IoT is facing many challenging issues to be a widespread technology, such as: battery lifetime limitation, poor computing and storage resources capacities. To cope with that, the Cloud model has been rethinked to bring more flexibility in the way the resources are managed in the IoT. Such a solution provides potentially unlimited computing and storage capabilities as well as many other services. In the literature, numerous architectures have been proposed to combine these two new technologies by introducing emerging computing paradigms such as FOG computing, EDGE computing, Mobile Cloud computing. In this paper, we survey the existing IoT-CLOUD architectures and we classify them by proposing a new taxonomy based on appropriate criteria, that we discuss the relevance.