I remember in 2016 my current employer provided the opportunity to go to the Cassandra Summit 2016 edition in San Jose. An exhausting and long 30-hour flight, tons of preparations with the US visa a few weeks ahead, a booking mistake that I had to pay with my own card until it was fixed and many more “troubles” later, I was finally there.
The thing about some conferences is that not all presentations are put online. In this case for Cassandra Summit 2016, the Datastax community has provided all recordings of the conference presentations but this is not true for most. Which is just nice of them to do for the community as such material can be later referenced to.