On 26 September 2019, the Swedish Rock Engineering Association organised a half-day symposium in Stockholm, Sweden, on underground space. After two inspiring presentations by prof. em. Ray Sterling and associate professor Jenny Normann, a discussion was held. ITACUS Activity Group Leader on Urban Resilience, Per Tengborg, and architect Elsa Wifstrand then introduced the idea of Think Deep Sweden. The ITACUS National Action Think Deep Program focusses on activating professionals at the national level to engage in a cross-discipline discourse on the use of underground space. National Think Deep groups are already active in the UK, Nigeria and Australia.