No, you canβt. Accordind to HTML 4.01 / XHTML 1.0 dtd you can only include inline elements in the span tag. This is the following:
a, object, applet, img, map, iframe, br, span, bdo, tt, i, b, u, s, strike, big, small, font, basefont, sub, sup, em, strong, dfn, code, q, samp, kbd, var, cite, abbr, acronym, input, select, textarea, label, button, ins, del, script.
It is not possible to quickly check HTML 5, but donβt think that it is here.