I'm not sure if everyone realises this, but you know how all of Katy's lead singles have gone #1 in the US? They've also all gone #1 in the UK, Canada and New Zealand.

(Part of Me peaked at #5 in Australia). So she has a WW record to maintain.
Teenage Dream's run is even more impressive in Canada tbh.
#1 California Gurls
#2 Teenage Dream
#1 Firework
#1 E.T.
#1 Last Friday Night (T.G.I.F.)
#2 The One That Got Away
#1 Part Of Me
#1 Wide Awake
ALL Top 2 hits.

TOTGA and WA moved up a spot, but TD dropped one.