> Why do we still use tanks in modern times?

Because a 120mm gun blows everything up. 120mm guns can do things such as:

1. High-explosive rounds (Chemical Energy, or CE) -- 50lbs of high-explosives delivered to a target will kill almost anything, even if that "thing" is hiding behind a tree, concrete, or even behind tank-armor.

2. Discarding Sabot / Kinetic Energy rounds (KE for short) -- 50 lbs of depleted-uranium darts flying at Mach 1.6 destroys a lot of things, in ways that are complementary to #1. You can shoot through entire houses with these darts.

3. Canister rounds -- 50lbs of "shotgun pellets" can clear 500+ meters. Yes, an entire-football field can be covered by a *SINGULAR* "tank shotgun" blast.

Kinetic-energy rounds travel faster but have higher-penetration at short-distances (because KE rounds have more room for explosives to "launch" the shell). However, KE-rounds are supersonic and therefore get hit by a lot of air-resistance/drag.

CE-rounds in contrast, travel much slower, but pack a lot of "explosives" at the end of their shot. As such, CE-rounds start off with much less penetration (bad at short-distances), but can be lobbed 3000 meters and still have just as much deadliness (since most of the "damage" of CE-rounds comes from the explosive, air-resistance literally doesn't matter aside from being computationally-difficult to aim. But modern computers can compensate easily these days)

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These are the three main-types of ammo that a 120mm gun uses (aka, a tank gun). Now some questions.

1. 120mm guns weigh something like 10-tons -- How do you move them? With a big engine.

2. But a big engine + the gun itself is a sitting duck against even a 50-cal sniper rifle. We should cover the engine + gun in armor, to protect the crew and equipment.

3. But armor weighs a lot (especially depleted uranium armor). So we need a *bigger* engine. But the bigger-engine needs more armor to protect it. Etc. etc. etc.

Eventually, we end up putting a LOT of armor, to cover the HUGE engine and the HUGE gun all together.

That's about it. You need tanks to destroy enemy bunkers (what else are you going to shoot? AT4 / Javelins? Those heavy and slow weapons only have 1 or 2 shots. Tanks have *40* shots, more than enough to overrun any bunker you come across).

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Tanks are your biggest gun on the battlefield. They have armor as minor amounts of protection, not to actually be immune to enemies (though in practice, the armor is so thick they're immune to many smaller weapons). But the #1 purpose of any tank is to fire its big 120mm gun as often as possible on the front lines.

Tank crews are __NOT__ used as "cover" or "shields" in the modern battlefield. They are just grounded large-gun platforms.

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> They seem useless in anything urban.

Wrong. Tanks are the only weapon large enough to damage enemy houses, bunkers, or other fortifications. If the enemy is hiding behind a concrete wall, the Tank-gun can shoot right *through* it and kill everyone on the other side.

Buttoned up tanks don't know where the enemy is however. (Tanks have night-vision and thermal-vision sensors, but can only focus those sights on a narrow line of vision) Tank crews rely upon friendly infantry to search for enemies. Tanks have awful visibility, but their big-gun is unparalleled on the battlefield.

https://www.youtube.com/watch?v=U61Hrn1JZWQ

Turns out that in practical urban combat, a lot of enemies hide behind concrete walls. What exactly is your battle-plan for that?

Tanks can provide air-burst (shoot over the wall, explode, rain fragments DOWN upon the enemy), or *THROUGH* the wall. Tanks are exceptionally flexible weapons.