Fatou's lemma says that
if $f_n:X \rightarrow [0,\infty]$ are measurable,then
$$\liminf_{n\rightarrow \infty}\left(\int_X f_n \,\mathrm{d} \mu\right) \geq \int_X \liminf_{n\rightarrow \infty} f_n \,\mathrm{d}\mu$$
I like to know what this Lemma really says. That is, how can I express in words (rather informally) what this lemma actually says?