I found the book by chance.
- Löysin kirjan sattumalta.
I found this restaurant by chance.
- Löysin tämän ravintolan sattumalta.
We met them by accident at the bus terminal.
- Tapasimme heidät sattumalta linja-autoasemalla.
I met Jane by accident.
- Tapasin Janen sattumalta.