In our roundup of travel stories this week: A collapsing sandcastle that trapped a teenager, the Vatican Observatory where science meets religion, plus “invisible architecture” in the African desert.

Few transport options capture romantic imaginations as completely as sleeper trains, those legendary locomotives that allow us to bed down in one world and wake up in another.

For rail fans, there are overnight routes to discover on six of the world’s seven continents. They range from deluxe hotels on wheels ferrying guests to places such as Machu Picchu and the Taj Mahal, to the transcontinental giants of Canada and the USA with their spectacular “Vistadome” panorama cars. Here are 10 of our favorites.

The release of the biopic “Tony” has renewed interest in superstar chef Anthony Bourdain. In 2014, he traveled to Russia on the eve of the Sochi Winter Olympic Games for CNN’s “Anthony Bourdain: Parts Unknown” and rode the luxury Grand Express sleeper train between Moscow and St. Petersburg. US-based subscribers can stream here.

Grand designs