The foreign exchange market – also called forex, FX, or currency market – was one of the original financial markets formed to bring structure to the burgeoning global economy. In terms of trading volume it is, by far, the largest financial market in the world. Aside from providing a venue for the buying, selling, exchanging and speculation of currencies, the forex market also enables currency conversion for international trade settlements and investments. According to the Bank for International Settlements (BIS), which is owned by central banks, trading in foreign exchange markets averaged $5.1 trillion per day in April 2016.
GBPNZD is approaching its resistance at 1.9620 (100% Fibonacci extension , 61.8% Fibonacci retracement , horizontal swing high resistance) where it is expected to reverse down to its support at 1.9062(38.2% Fibonacci retracement , horizontal swing low support). tochastic (89, 5, 3) is approaching its resistance at 96% where a corresponding reversal is expected....
The main trading centers are London and New York City, though Tokyo, Hong Kong, and Singapore are all important centers as well. Banks throughout the world participate. Currency trading happens continuously throughout the day; as the Asian trading session ends, the European session begins, followed by the North American session and then back to the Asian session.
Governments / Central banks – A country’s central bank can play an important role in the foreign exchange markets. They can cause an increase or decrease in the value of their nation’s currency by trying to control money supply, inflation, and (or) interest rates. They can use their substantial foreign exchange reserves to try and stabilize the market.
In this view, countries may develop unsustainable economic bubbles or otherwise mishandle their national economies, and foreign exchange speculators made the inevitable collapse happen sooner. A relatively quick collapse might even be preferable to continued economic mishandling, followed by an eventual, larger, collapse. Mahathir Mohamad and other critics of speculation are viewed as trying to deflect the blame from themselves for having caused the unsustainable economic conditions.

In the above example, we bet that the EUR will go up against the USD, so we bought EUR/USD hoping to sell it later at a higher price. This is called long position. What should you do if you expect the EUR to go down against the USD? Well, then you do the opposite - you sell the EUR/USD with the hope to buy it cheaper later on. This short trading is how you take advantage of exchange rates that are going down.

The foreign exchange market works through financial institutions and operates on several levels. Behind the scenes, banks turn to a smaller number of financial firms known as "dealers", who are involved in large quantities of foreign exchange trading. Most foreign exchange dealers are banks, so this behind-the-scenes market is sometimes called the "interbank market" (although a few insurance companies and other kinds of financial firms are involved). Trades between foreign exchange dealers can be very large, involving hundreds of millions of dollars. Because of the sovereignty issue when involving two currencies, Forex has little (if any) supervisory entity regulating its actions.

Once Nixon abolished the gold standard, the dollar's value quickly plummeted. The dollar index was established to give companies the ability to hedge this risk. Someone created the U.S. Dollar Index to give them a tradeable platform. Soon, banks, hedge funds, and some speculative traders entered the market. They were more interested in chasing profit than in hedging risks. 
You may have noticed that the value of currencies goes up and down every day. What most people don't realize is that there is a foreign exchange market - or 'Forex' for short - where you can potentially profit from the movement of these currencies. The best known example is George Soros who made a billion dollars in a day by trading currencies. Be aware, however, that currency trading involves significant risk and individuals can lose a substantial part of their investment. As technologies have improved, the Forex market has become more accessible resulting in an unprecedented growth in online trading. One of the great things about trading currencies now is that you no longer have to be a big money manager to trade this market; traders and investors like you and I can trade this market.
In the context of the foreign exchange market, traders liquidate their positions in various currencies to take up positions in safe-haven currencies, such as the US dollar.[88] Sometimes, the choice of a safe haven currency is more of a choice based on prevailing sentiments rather than one of economic statistics. An example would be the financial crisis of 2008. The value of equities across the world fell while the US dollar strengthened (see Fig.1). This happened despite the strong focus of the crisis in the US.[89]
Starting with $500 will produce more daily income than starting with $100, but most day traders will still only be able to make $5 to $15 per day off this amount (with regularity). If you start with $5000 you have even more flexibility and can even day trade forex with mini and standard lots (as well as micro lots). If you buy the EUR/USD at 1.3025 and place a stop loss at 1.3017 (8 pips of risk) what position size do you take?
The need to exchange currencies is the primary reason why the forex market is the largest, most liquid financial market in the world. It dwarfs other markets in size, even the stock market, with an average traded value of around U.S. $2,000 billion per day. (The total volume changes all the time, but as of August 2012, the Bank for International Settlements (BIS) reported that the forex market traded in excess of U.S. $4.9 trillion per day.)