This is the 136th most frequent Czech word.
prahy
"Prahy" in Czech means "thresholds" or the plural of "práh".
In this sentence, 'Prahy' (Prague's) is used in the genitive case to indicate possession, showing what kind of beauties were seen.
Viděli jsme krásy Prahy při naší cestě.
We saw the beauties of Prague during our trip.
Here, 'prahy' (thresholds) is used in the nominative plural to describe the physical parts of the doors that complicate crossing.
Dveře měly velmi vysoké prahy, což nám ztěžovalo přechod.
The doors had very high door thresholds, which made our crossing difficult.
In this example, 'prahy' (threshold) appears in the genitive singular to indicate the threshold being touched by the brush.