New observational methods often trigger new discoveries in astronomy. To explore the universe in an innovative way, we are constructing a multiple telescope, the 7-dimensional telescope (7DT) in Chile. 7DT is made of twenty, 0.5-m diameter wide-field telescope, and the first ten units started the operation in October, 2023, with the expected completion of the full system in 2024. With 7DT, we will perform the 7-dimensional sky survey (7DS), a wide-field, time series, spectral mapping of the southern sky. The survey aims to (i) understand the spectral variability of astronomical sources through time-series spectral mapping such as active galactic nuclei; (ii) provide a spectral map of the sky that can be used to study spatially resolved stellar population of galaxies, cosmology, etc; and (iii) rapidly identify electromagnetic counterparts of gravitational-wave sources for successful multi-messenger astronomy. In this talk, we will introduce 7DT and 7DS and outline the unsolved problems that 7DS will tackle. We will also early images and the data taken with 7DT as well as its current performance, which demonstrate the scientific promises of 7DS. We will also briefly discuss the synergies between 7DT and KASI’s initiatives such as SPHEREx, KMTNet, and the Vera Rubin Observatory.