Additively manufactured architectures via processes such as powder bed fusion and direct energy deposition are typically limited to solids, and so-far fabrication of liquid-solid composites is not possible. In this study, we show that the encapsulation of liquid inside metal microscale vessels is indeed feasible using a recent additive micromanufacturing technique based on localized electrodeposition. We successfully fabricated liquid filled 3D copper microarchitectures and confirmed the existence of liquid via cross-sectional analysis using a focused ion beam at cryogenic temperature (cryo-FIB). The volume of the liquid encapsulated in the microvessels varied from pico-liters to micro-liters based on the geometry of copper microarchitectures. 3D reconstructions of the liquid filled copper microarchitectures using nano computed tomography (NanoCT) revealed the dense microstructure of copper walls, which prevents the liquid from escaping. Further, fundamental micromechanical properties of the liquid-containing copper microarchitectures will be presented as a function of strain rates and temperatures. Depending on the phase and the volume fraction of encapsulated liquid, the microarchitectures show remarkably different stress levels and strain rate dependency. Along with the microstructural and mechanical characterizations, the feasibilities and potentials of liquid encapsulation at the microscale as new structural and multifunctional 4D materials will be discussed.