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 silver European coins. 154 junk-copper U.S. pennies contain a full pound of .950 fine copper. Junk silver Junk silver is an informal term used in the United States, United Kingdom, Canada and Australia for any silver coin which is in fair or cull condition and has no numismatic or collectible value above the bullion value of the silver it contains. Such coins are popular among people seeking to invest in silver, particularly in small amounts. The word "junk" refers only to the value of the coins as collectibles and not to the actual condition of the coins; junk silver is not