Grand Challenges are ranked and defined to guide an area/discipline so that efforts and long term initiatives focus on providing disruptive solutions. These challenges represent a key component to highlight core issues that cannot be tackled in a short term or by a single person, requiring multiple efforts and sometimes whole communities. This position paper presents a discussion involving activities of the Brazilian Human-Computer Interaction (HCI) community in the 2012-2017 period in the context of the challenge Future, Smart Cities and Sustainability, which is part of the Grand Research Challenges in Human-Computer Interaction in Brazil (GranDIHC-BR). The analysis performed shows that this challenge is one of the least addressed by the Brazilian HCI community and that actions fommenting GranDIHC-BR must be taken continuously, e.g., conferences, competitions, or submission tracks related to GranDIHC-BR challenges less covered by the Brazilian HCI community. From the presented results, one expects to summarize: (1) activities performed in the context of the challenge, (2) reflections around the theme, and (3) to outline a research agenda for the next 5 years.