Love in a time of swine flu: As swine flu spreads from its apparent epicenter in Mexico to countries as far away as Israel and New Zealand, the World Health Organization (WHO) raised its influenza alert level from Phase 3 to Phase 4 on its six-level scale on April 27. Phase 4 "indicates a significant increase in risk of a pandemic but does not necessarily mean that a pandemic is a forgone conclusion." Above, a couple doesn't let swine flu get in the way of their public display of affection at Mexico City's Historic Center (Centro Histórico) on April 25.