Bitcoin is the strongest currency in the world  even now the price is 6701 USD. Just imagine  the price of bitcoin last year this time it was USD1000 or below. At present the market trend is bearish mean time the market is expecting that the trend may change at any time to bullish. So there is not any other currency matching with bitcoin in the price value.Its present market capital is 114 billion USD and its daily trading volume also very high and so bitcoin is the strongest currency in the world