Integrated Ocean Drilling Program Expedition 347 aimed to retrieve sediments from different settings of the Baltic Sea, encompassing the last interglacial-glacial cycle to address scientific questions along four main research themes: 1. Climate and sea level dynamics of marine isotope Stage (MIS) 5, including onsets and terminations; 2. Complexities of the latest glacial, MIS 4-MIS 2; 3. Glacial and Holocene (MIS 2-MIS 1) climate forcing; and 4. Deep biosphere in Baltic Sea Basin (BSB) sediments. These objectives were accomplished by drilling in six subbasins: (1) the gateway of the BSB (Anholt), where we focused on sediments from MIS 6-5 and MIS 2-1; (2) a subbasin in the southwestern BSB (Little Belt) that possibly holds a unique MIS 5 record; (3, 4) two subbasins in the south (Bornholm Basin and Hanö Bay) that may hold long complete records from MIS 4-2; (5) a 450 m deep subbasin in the central Baltic (Landsort Deep) that promises to contain a thick and continuous record of the last ~14,000 y; and (6) a subbasin in the very north (Ångermanälven River estuary) that contains a uniquely varved (annually deposited) sediment record of the last 10,000 y. These six areas were expected to contain sediment sequences representative of the last ~140,000 y, with paleoenvironmental information relevant on a semicontinental scale because the Baltic Sea drains an area four times as large as the basin itself. The location of the BSB in the heartland of a recurrently waning and waxing ice sheet, the Scandinavian Ice Sheet, has resulted in a complex development: repeated glaciations of different magnitudes, sensitive responses to sea level and gateway threshold changes, large shifts in sedimentation patterns, and high sedimentation rates. Its position also makes it a unique link between Eurasian and northwest European terrestrial records. Therefore, the sediments of this largest European intracontinental basin form a rare archive of climate evolution over the latest glacial cycle. High sedimentation rates provide an excellent opportunity to reconstruct climatic variability of global importance at a unique resolution from a marine-brackish setting. Comparable sequences cannot be retrieved anywhere in the surrounding onshore regions. Furthermore, and crucially, the large variability (salinity, climate, sedimentation, and oxygenation) that the BSB has under