Creeping vine has me stumped

While standing on the balcony of friends’ flat this weekend on a trip to the coastal Kwa-Zulu Natal town of Illovo, I spotted these beautiful bulbous flowers. They appeared to be growing on some sort of vine creeping up a tall tree alongside his townhouse flat.

creeper

I tried searching the internet, but have not been able to identify it. I have no idea what type of tree it is either. Anyone with answers?