Conference: CppCon (C++, US)

The conference for C++ is CppCon. If you want to hear (and see) the author of the language speaking, see the conference archive:
https://cppcon.org/

Quoting:
"In the meantime, look for slides and source code for your favorite CppCon 2017 sessions at our presentation material repository.

You can find the posters that were entered in the CppCon 2017 Poster Competition in the poster repository.

You can also watch CppCon 2017 session videos on YouTube and Channel 9. Some of them are already available on the CppCon YouTube channel in the CppCon 2017 playlist."

CONFERENCE: GDG DevFest Season 2017 (PT)

GDG DevFest Season 2017 - Coimbra (PT), 2017-12-09

Quoting:
"The biggest Google tech conference in Portugal: All about Android, Web, Cloud and Security from the world experts"

Additional info:
Day 1 agenda: https://devfest.gdgcoimbra.xyz/schedule/day1
About the Google Developers Group (Coimbra city): http://gdgcoimbra.xyz/