Pontoon bridge in 638. The army of the Umayyad Caliphate built a pontoon bridge over the Bosporus in 717 during the Siege of Constantinople (717–718). The Carolingian army of Charlemagne constructed a portable pontoon bridge of anchored boats bound together and used it to cross the Danube during campaigns against the Avar Khaganate in the 790s. Charlemagne's army built two fortified pontoon bridges across the Elbe in 789 during a campaign against the Slavic Veleti. The German army of Otto the Great employed three pontoon bridges, made from pre-fabricated materials, to rapidly cross the Recknitz river at the Battle on the Raxa
Junk food poll" (Baltimore); "Celebrities' favorite junk food" (Los Angeles); "A Nutritionist's Guide to National Junk Food Day" with "Rules for Splurging" ("Huffington Post"); and "It's National Junk Food Day: Got snacks?" (Kansas City). It is well-established that the poor eat more junk food overall than the more affluent, but the reasons for this are not clear. Few studies have focused on variations in food perception according to socio-economic status (SES); some studies that have differentiated based on SES suggest that the economically challenged don't perceive healthy food much differently than any other segment of the population. Recent research into scarcity, combining