Worst epic science fail you have seen in sci-fi?

[stevebowers]

Did anything in Niven's Ringworld books say the Puppeteers were human sized?

The puppeteers in the books were antelope- or deer-sized, big enough to kick you in the face if necessary. But their large buildings might be mostly empty space inside - they are creatures of grassland, so I imagine their buildings to be large tracts of veldt enclosed in an artificial environment, layered on top of each other with relatively high ceilings, and stepping disks to get from one layer to another.

In OA we have elephant provolves- if they have any architecture at all, it might be similar, but significantly larger. Since OA doesn't have stepping disks, the various levels would need to be connected by ramps or lifts.
Spiral ramps for elephants would be an interesting architectural feature.
Here's an equestrian ramp in the Round Tower in Copenhagen. An elephant ramp would be at least twice as large, although not necessarily less steep.