In this Chapter, we describe the phenomenology of multilevel financial networks. Network analysis represents a useful tool for the analysis of financial systems, allowing, in particular, for a better understanding of the mechanics of systemic distress. However, the level of complexity reached by the financial system, coupled with the linkages arising to and from other economic sectors, calls for a more integrated approach that takes into account a whole series of networks. In this Chapter, we therefore describe the financial systems as a nexus of interconnected networks. By reviewing selected theoretical and empirical works and describing two methodological extensions for DebtRank, we show different arguments in favor of the adoption of a broader view of the network approach to finance.