If you click on this link, you can see a list of churches which existed in Frankfurt before the two world wars.
Amongst those with high towers are St. Bartholomew's cathedral; the Church of the Magi; St. Katherine's Church; St. Paul's Church; and St. Peter's Church.
Perhaps the church mentioned in Heidi was St. Peter's. In the picture on the left, it is possible to see a small ball on the top of the tower (but not possible to see whether it is gold!). St. Peter's church was rebuilt in 1895.
A hurdy-gurdy is a type of street organ or barrel organ. This is a mechanical musical instrument which is played by turning a handle. Inside the barrel organ is a cylinder studded with pins and staples. As this cylinder is turned, different tunes are played automatically.
Those who played barrel organs in public to earn money used to be known as organ grinders. Sometimes their barrel organs were free standing; sometimes they had to be carried. Some organ grinders had performing monkeys as an extra attraction.
Perhaps the 'extra attraction' of the little boy in Frankfurt was the tortoise.
In the German version of Heidi, the little boy asks Heidi to give him 'zwanzig Pfennige' ('20 pfennigs').
(In German the plural of Pfennig is Pfennige. Like all nouns in German, these words begin with a capital letter.)
Ornamental door knockers are common in many countries.
In some English versions of Heidi, the tabby kitten is described as being 'striped white and yellow'.
The colour of Tabby cats' coats may vary a great deal, but they are always mottled, and contain more than one colour.
Probably the most well-known tabby cat is the one with a brown, black, and fawn stripy coat. This kind of tabby often has a mark on its forehead which looks like the letter 'M'.
Because Heidi has been brought up in Switzerland, she would speak Swiss German (Schweizerdeutsch). The little boy would speak the dialect of German spoken in Frankfurt (click here for more information).
Four languages are spoken in Switzerland. These are Swiss German, French, Italian and Romansch. There is only a very small number of Romansch speakers (less than 1% of the population). Most of these live in the canton of Grisons (Graubünden) where Heidi's story is set.
The map on the left shows the French area (lilac); the Swiss German area (pink); the Italian area (green); and the Romansch area (yellow).
In the video below, Roger Federer, the well-known tennis player, is speaking Swiss German.
Nouns and adjectives in some languages vary according to their number, gender and case. This is called declension. School children often had to decline a noun out loud, listing its various forms. For example, to decline the plural of the Latin word puella (girl) you would recite: puellae, puellae, puellas, puellarum, puellis, puellis.
To learn more about the meaning of the Latin declensions, click here.