This is why Equestria needs a standing military force… especially with how they were becoming more “global” and outreaching in the latter part of the series. Surrounded by friendly and hostile neighbours alike.
I never understood why a nation as large and supposedly powerful as Equestria doesn’t have any form of defense. When the villains could just simply waltz into the capital that is situated at the heart of their territory without being as so much as being detected by anyone.
Given how shoddily run Equestria is as a country, it’s not surprising that they eventually collapsed in the near future sometime after the Mane 6’s time.

You’d think Celestia would have buffered up Equestria through the thousand years of her rule given the myriad of shit she and the land had went through in their history.

@Cartoonbondage101  
Captain of the Royal Guards: Citizens of Equestria, we’re under attack! Scramble!

@ЅℰℒᎯℙℋℐℰℒ  
I guess they tried to stop the Storm King, Tempest, Grubber, and the Storm Creatures from conquering Canterlot and the rest of Equestria but we’re captured and enslaved.

This was always how I imagined a full scale invasion of Canterlot by a foreign power.  
Though, my version would involved another Pony nation invading Equestria with an armada of airships, and legions of pegasi ponies armed with spears and crossbows emerging from the hatches on the ships as aerial fighters. With unicorns and earth pony ground battalions stepping off the ships as they land.

The airship looks much better there.

Man. 
This reminds me of one piece if art I found in Fur affinity that was apparently commissioned by an edgelord furry who had a hate boner for ponies and Baronies. 
>>104255 Grimdark btw

Bronies finally reach Equestria.

@Cartoonbondage101 
All that’s missing is Rainbow Dash running out of Pony Joe’s Doughnut Shop.

The royal guards are likely up on the battlements going “Hey, it’s ok, Twilight’s there. We’ll just wait for her… oh no… no. She’s just got her ass kicked. That edgelord pony with the broken horn just curbstomped her. Ok… well, everyone good with rolling over and surrendering? Yeah? Great.”

They attack canterlot this is like destiny 2 and the tower being attacked

Where are the Royal Guards…?