The Tuvaluan Dollar is the currency of Tuvalu - a small nation in the Pacific Ocean. Tuvalu has never had banknotes of its own, and has been issuing coins since 1976; these circulate together with coins of the Australian Dollar, which is also legal tender in the country, and to which the Tuvaluan Dollar is pegged.
The Australian Perth Mint issues a large variety of non-circulating legal tender coins under the authority of Tuvalu. Some of these are in the silver ounce format (abbreviated as 1 oz). Strictly speaking, they are not bullion as they are priced at a premium and are targeted at collectors who appreciate them for their artistic merit and collectable value and not just for their precious metal content.
This coin is part of the Marvel Coin Series - silver bullion coins depicting characters from Marvel comics, and features Captain America.
The mint says about it:
During WWII, the frail but courageous Steve Rogers was injected with an experimental Super Soldier serum, emerging from the treatment as the pinnacle of human physical potential. Outfitted with a patriotic costume and iconic shield, he became the legendary Captain America! Though frozen in ice for decades after a climactic battle, Cap re-emerged in modern times, continuing the battle against evil as the leader of the Avengers.
His first appearance was in 1941 in the Captain America Comics #1. | 
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