For decades, investors who were courageous enough to "buy on the dips" caused by North Korea concerns ended up making money, according to Erin Browne, head of asset allocation at UBS Asset Management.
"I'll tell you why, and they should be very nervous".
'Stock markets in Europe are still under pressure because of the heightened tensions surrounding North Korea, ' said David Madden, market analyst at CMC Markets UK. "His sick mind and reckless conduct could consume the lives of millions".
To that end, gold prices shot up to near $1,300 an ounce - their highest level in several months.
The jump in the franc had prompted hedge funds to unwind leveraged positions which involved borrowing in the weak Swiss currency and investing the proceeds in the relatively higher-yielding Australian dollar and the Canadian dollar.
The Dow Jones industrial average lost 71 points, or 0.3 per cent, to 22,013.
Sterling touched a three-week low against the dollar as mixed output and trade data did little to alter investors' downbeat view of an economy struggling to meet Bank of England targets. The Volatility Index increased 39% to 15.41, a level not seen since mid-May.
The MSCI World index slipped 0.1 per cent, extending Thursday's 1.1 per cent drop, its biggest one-day slide since May 17, hurt by the escalating US-North Korea tensions.
The attraction of the franc in the face of the Korean situation, however, has pulled it back from long-term lows hit earlier this month.
The Nasdaq composite lost 18.13 points, or 0.3 percent, to 6,352.33.
Away from the geopolitical drama, USA inflation data is due at 1330 GMT.
As investors sold stocks around the world, assets perceived as havens - such as gold, the Japanese yen and USA government bonds - strengthened.
Against the greenback, the Swiss franc eased about 0.1 percent to 0.9645 per dollar, having surged about 1.1 percent on Wednesday.
"There is a continuation of flight to the safe havens after remarks on Thursday evening from Trump about North Korea", said Quantitative Commodity Research consultant Peter Fertig.
And in bond markets, 10-year U.S. Treasuries and Germany's ultra-safe government bonds, known as Bunds, were trading at their highest prices since June.
It had retreated to trade nearly flat on the day at 109.17 yen per dollar by 0711 GMT but was still 0.2 percent stronger against the euro at 128.28 yen. It soared over 2 per cent in the previous two sessions, and is set for a weekly gain of 2.25 per cent.
Benchmark U.S. crude rose 39 cents to settle at $49.56 a barrel on the New York Mercantile Exchange. Netflix fell 3.2 per cent.