Herge liked to mix real and fictional geography in his story-telling, sometimes explicitly and sometimes implicitly.
Machu Picchu doesn’t appear directly in the books but it can be assumed as the basis for the temple in The Seven Crystal Balls / Prisoners of the Sun. Located high in mountains, in a remote part of Peru, it was the last strong hold of the Incas. A sacred site, one of the main buildings is called the Temple of the Sun. The site was ‘discovered’ and made famous in 1911 by the American explorer and historian Hiram Bingham.
This facade appears in The Red Sea Shark though you may be more familiar with it from Indian Jones and the Last Crusade. In reality it is in Petra, an ancient city in modern-day Jordan and is one of the true wonders of the world. At its peak, around 200AD, it was a city of over 20,000 people with a sophisticated water management system that allowed the city to thrive in the middle of a desert.
Loch Lomond itself never appears in the books but it is a name familiar to all Tintin fans as Captain Haddocks favourite tipple. It is particularly prominent in The Black Island as Tintin visits Scotand but it crops up regularly in a number of books. There is a real world Loch Lomond Distillery who do tours. So, if you are ever in Scotland, call in, see how they make the whisky and have a wee dram for Captain Haddock.