Foreign exchange (FX) is the largest financial market in the world, trading about $7.5 trillion a day (BIS (2022b)). It operates 24 hours a day, five and a half days a week.Project Mariana looks to the future and envisions a world in which central banks have issued central bank digital currencies (CBDCs) and explores how foreign exchange (FX) trading and settlement might look. Mariana borrows ideas and concepts from decentralised finance (DeFi) and studies whether so-called automated market-makers (AMMs) can simplify FX trading and settlement with a view to enhancing market efficiency and reducing settlement risk.Project Mariana is a proof of concept (PoC) for a global interbank market for spot FX featuring both an AMM and wholesale CBDCs (wCBDCs). In the PoC, wCBDCs circulate on domestic platforms and so-called bridges allow them to be moved on to a transnational network that hosts the AMM. Project Mariana extends previous experimentation on cross-border settlement using wCBDC arrangements and distributed ledger technology. It successfully demonstrates the technical feasibility of the proposed architecture and adds novel insights on the potential of tokenisation in three dimensions