Unfortunately, you can't assume that Bitcoin is legal everywhere you go -- it's safe to use the digital cash in some countries, but it's mostly verboten in others. However, you won't have to travel blind. The US' Law Library of Congress has just published a report (PDF) that outlines Bitcoin's legal status in 40 countries. In short, the currency mostly exists in a gray area. While countries like Germany and Finland have cleared Bitcoin for legal use in some conditions, most nations either haven't regulated it or see it as too risky. Don't leave your physical wallet at home on your next vacation, then.