Course profile and typical conditions for each one, so Race Day Mode can tell you what the day will actually cost before you set a goal.
Twenty countries. Every major, and a lot that aren't.
Temperatures are the climate normal for that race's month and city — what to expect, not a forecast. Meridian swaps in the real forecast once the race is close enough for one to exist.
Real elevation profiles. Every course here carries its published total climb and a plausible shape, which is enough to tell Boston from Berlin but not enough to tell you what mile 21 will feel like.
Proper mile-by-mile profiles need survey data we do not have, and scraping them off race organisers' maps would be both rude and probably unlawful. It is on the list, labelled honestly until it is done.
Tell us which, and we will make sure that course is properly modelled before the beta.