Memorial Hall

Memorial Hall (メモリアルホール) is a location in Mega Man X4, a military building built solely by the elite anti-Maverick military organization known as the Repliforce to not only to serve as their main headquarters but also as the symbol of commemoration to their own members, most commonly those who have fallen in the ongoing Maverick Wars.

Description
Memorial Hall can be seen in the cutscene after the opening stage. Repliforce holds a large assembly in the hall, where General formally announces their coup d'etat to separate from the rest of the world, launch a Reploid-only nation, and become a fully independent organization.

After X or Zero defeats the first four Stage Select Screen bosses, Colonel challenges them to come duel him at Memorial Hall. X's encounter with Colonel is a boss battle taking place just outside Memorial Hall, with the large structure in the middle visible in the background, while Zero's encounter is a cutscene wherein the two fight right in front of the structure before being interrupted by Iris.

Rockman X4 manga
In the Rockman X4 manga, Memorial Hall makes an appearance in the second chapter "Uprising". Just like in the game, the leader of the Repliforce, General, gives a public speech in front of his troops attacking the human government for ordering them to disarm due to the organization being suspected of involvement in Eregion's attack on a metropolitan city. The General says that they will never submit to such a command, and that they consider their weapons to be their pride with death being the only thing that will make them let go of their weapons. General says that from this point forward, the Repliforce will become an independent organization. The speech is broadcast live to the human public at 1:00 PM via Repliforce blimps that are flying across the skies. Repliforce sub-commanders Frost Walrus, Jet Stingray, Storm Owl, Web Spider and Slash Beast are on the stage during the speech, along with the Colonel.