Research on temporal aspects of information retrieval has recently gained considerable interest within the Information Retrieval (IR) community. This paper describes our efforts for building test collections for the purpose of fostering temporal IR research. In particular, we overview the test collections created at the two recent editions of Temporal Information Access (Temporalia) task organized at NTCIR-11 and NTCIR-12, report on selected results and discuss several observations we made during the task design and implementation. Finally, we outline further directions for constructing test collections suitable for temporal IR.