Also known as gentians.
Floria Tosca is the heroine of Giacomo Puccini's opera Tosca. The Castel Sant'Angelo is a fortress in Rome, sometimes known as the Mausoleum of Hadrian. At the end of Act 3 of the opera, Tosca commits suicide by jumping from its battlements.
Listen here to Maria Callas and Giuseppe di Stefano (in the roles of Floria Tosca and Mario Cavaradossi) singing the final aria of Act 3, Amaro sol per te m'era il morire ('Only for you did death taste bitter for me').
Listen to the aria here on Spotify
Assuming we're in Lima, Peru, Messner is probably talking about Machu Picchu, or one of the other Inca sites.
Machu Picchu is an abandoned fifteenth century Incan town in Peru. Its beautiful situation high up in the mountains above the Urubamba Valley, combined with its impressive state of preservation, make it one of the most popular tourist destinations in the country.
Machu Picchu was voted one of the Seven Wonders of the Modern World in 2007. The site is an extremely lucrative source of income for Peru, but in recent years concerns have mounted over the impact high volumes of tourists are having on Machu Picchu's preservation. UNESCO, who gave the site World Heritage status, are currently considering putting it on the list of endangered heritage sites.
The pisco sour is a South American cocktail.
Pisco, a type of brandy, is Peru's national drink.
Combine a double measure of pisco with a large spoon of sugar, juice of one lime and an egg white. Shake with ice.