returned to Europe at the end of August to take part in the G7 summit in Biarritz, France. The President announced prior to his trip that he was postponing a visit to Denmark because of the negative reaction of Prime Minister Mette Frederiksen to Trump's reported interest in purchasing the island of Greenland from the country. Frederiksen has called the idea "absurd" on Twitter. Later on, Trump also cancelled his visit to Poland (which would have been his second one) to return to the U.S. early because Hurricane Dorian was approaching the country.
The U.S. president has been to France four times (three times for bilateral visits with French President Emmanuel Macron), making it the country with the most Trump visits in the world. Germany, on the other hand, also a long-time U.S. ally, has only seen a Trump visit once, for the G20 summit in Hamburg in 2017. A bilateral visit with chancellor Merkel is still not on the agenda, which is highly unusual given the close cooperation of the two countries. Trump has also stopped by at Ramstein airbase in South-West Germany in 2018, but this visit is not counted as a visit to German territory by the State Department.
Another country that Trump has frequented is Japan (two state visits and one summit visit). The most unusual country that Trump has visited is certainly North Korea, which the president walked into for about a minute when meeting Nortk Korean leader Kim Jong-un in the Korean Demilitarized Zone. No other sitting president had stepped foot in the country before and it is not yet clear if that visit will be counted by the Office of the Historian at the State Department.