Abstract: A cell culture device (10) of the cultivation of cells. The cell culture device (10) includes a plurality of trays (12a, 12b, 12c, 12d), each tray (12a, 12b, 12c, 12d) having a cell growth surface (20) and at least one wall (22, 24) extending upwardly from the cell growth surface (20). The at least one wall (22, 24) is configured to receive an additional tray thereon. A ratio of the number of the plurality of trays (12a, 12b, 12c, 12d) per a height dimension of the plurality of trays (12a, 12b, 12c, 12d) is greater than or equal to about 1 tray per 12 mm.