Halloween proved to be a scream for the euro, which saw its steepest one-day decline in 16 months Thursday - a move some analysts say suggests recovery hopes could have been premature. Sean Callow, senior currency strategist at Westpac, told CNBC he was surprised by the steepness of the euro's fall. "There is a lot of talk about a recovery in the euro zone... which is definitely premature in our book. This move is a reminder that European officials face very serious challenges," he said. A slew of weaker-than-expected data out of the euro zone Thursday, combined with Wednesday's less-dovish-than-expected Federal ... (full story)