I toured the USS Massachusetts, the 680-foot battleship that fired the last shot of World War II. Take a look inside.

Commissioned in 1942 and decommissioned in 1947, the USS Massachusetts earned 11 battle stars in World War II.

The USS Massachusetts was one of four battleships built as part of the South Dakota class, which was designed to be more compact than previous battleship classes.

The historic battleship is now a museum and war memorial at Battleship Cove in Fall River, Massachusetts.

I visited Battleship Cove in January, when the museum operates with limited winter hours due to the frigid temperatures on board the ships. The full list of hours of operation can be found on Battleship Cove's website.

General admission costs $25 per adult.

At 680 feet long — nearly the length of two football fields — I could see how the ship earned the nickname "Big Mamie."

The ship weighed 44,519 tons when fully loaded for combat.

Battleship Cove has four self-guided tour paths aboard the ship centered on four themes: Below Deck, World War II, Crew, and Topside.

The Below Deck tour takes visitors through the inner workings of the ship's technology, including the engine room, the gun plotting and handling rooms, and the radio room.

The World War II-focused tour features historical exhibits about the war as a whole and spotlights some of the battle damage the ship endured.

The Crew tour brings visitors through spaces that were part of the sailors' daily life on board, such as their bunks, galley, and laundry room.

The Topside tour explores the deck of the ship, including its many guns.

Color-coded arrows direct visitors along each of the routes.

I started with the Topside tour and was immediately overwhelmed by the enormity of the 16-inch guns.

The ship has a total of nine 16-inch, 45-caliber Mark 6 guns: two three-gun turrets at the front of the ship ("forward") and one three-gun turret at the back ("aft"). They could hit targets up to 23 miles away.

The 16-inch measurement refers to the bore diameter, or the size of the hole that the shell is fired through. The cannons themselves are over 60 feet long.

Even a single shell from the ship's 40-millimeter Bofors guns could take down an enemy aircraft.

The Bofors 40-millimeter guns featured a range of 6.25 miles and could fire between 120 and 160 rounds per minute.

At the height of World War II, the USS Massachusetts was outfitted with 72 40-millimeter guns.

The 20-millimeter Oerlikon autocannons served as another antiaircraft measure.

The 20-millimeter Oerlikon autocannons featured a range of 2.75 miles.

The battleship was also outfitted with 20 5-inch guns that fired 55-pound projectiles with a range of 10 miles.

Some of the ship's 5-inch guns still work and are used for ceremonial gun salutes.

If you look closely, you can see the seagull that decided to perch on one of the guns when I visited.

The deck of the USS Massachusetts included the ship's flag bag, which held the nautical flags used to signal and transmit messages to other ships.

Each nautical flag represents a letter or signal. For example, the flag representing the letter "O" can also mean "man overboard."

The ship's signal searchlight functioned as an additional communication device.

Crew members opened and closed the light's shutter to send messages in Morse code.

Inside the ship, the wardroom, which once functioned as the officers' dining room, has been converted into a lobby of sorts.

When the ship was deployed, officers would have eaten their meals here off fine china.

The wardroom still features tables and seating for large groups.

Tours begin with the memorial room, which lists the names of over 13,000 service members from Massachusetts who died in World War II.

In addition to functioning as a museum, Battleship Cove is the official World War II memorial for the Commonwealth of Massachusetts.

The Crew tour took me through several rooms full of floor-to-ceiling bunks known as racks.

During World War II, the crew of the USS Massachusetts grew from its normal number of 1,793 enlisted men to 2,500. When the berthing rooms were full, the ship set up hammocks in other areas.

The ship's post office, where sailors received letters from home, was crucial for maintaining crew morale.

Officers were in charge of censoring crew members' letters to their loved ones, blacking out information like their location or even the weather.

In the blacksmith shop, crew members made parts for anything on the ship that needed repairs or replacements.

During the war, maintenance had to be performed while the ship was in the middle of the ocean.

Today, museum volunteers use 3D printers to create replacement parts.

The ship's main galley was open 24 hours a day, seven days a week.

The galley prepared four meals per day: breakfast, lunch, dinner, and midnight rations known as "mid-rats."

Crew members baked around 500 loaves of bread per day in the bakery.

The bakers' work started at 3 a.m.

The laundry room was nicknamed "the harbor of lost clothes."

Sailors labeled every item of their clothing, but some items still ended up in the lost-and-found, known as the "lucky bag."

Sailors who disobeyed orders or neglected their duties were confined to the ship's jail, known as the brig.

In the brig, sailors received only bread and water for meals.

Along the World War II-themed tour route, I encountered a section of the USS Massachusetts damaged by enemy fire.

During the Battle of Casablanca in 1942, an 8-inch projectile hit the main deck and exploded in a bunk room. No one was injured since all of the sailors were at their battle stations, but the ship sustained damage from the shrapnel.

The holes have since been repaired, but red outlines on the walls show where they once were.

The tour also passed through the sick bay, which included doctors' offices, an operating room, and a dispensary.

The sick bay treated battle wounds as well as everyday ailments such as ear infections or athlete's foot.

This long passageway on the third deck was known as Broadway. Now it's part of the Below Deck tour route.

On Iowa-class battleships like the USS New Jersey, Broadway is the longest, straightest passageway on the ship. On South Dakota-class battleships like the USS Massachusetts, Broadway is thinner and not built in a straight line since the class was designed to be more compact.

In the 5-inch lower handling room, gunner's mates sent projectiles up to be fired from the 5-inch guns.

Gunner's mates loaded shells and powder cases into the hoists, which moved them up to the upper handling room and then up to the gun mounts.

The 16-inch gun turrets featured a similar setup, with a powder-handling room and hoists on the lower level.

Six powder bags were required to fire one 16-inch projectile.

The 16-inch projectiles, which were kept inside the gun turret, were about as tall as me. For scale, I'm 5-foot-3.

The USS Massachusetts could hold over 1,200 projectiles.

The massive 16-inch guns were aimed and fired with instruments in the plotting room.

A device called a Mark 8 Rangekeeper computed where to aim the 16-inch guns based on factors such as the ship's course and speed and the direction of the wind.

The USS Massachusetts had four engine rooms.

Eight boilers supplied steam to the ship's four General Electric steam turbines, which drove its four propellers.

The ship reached a top speed of 27.5 knots, or around 31.6 miles per hour.

The ship's electricity was managed from the distribution room.

In order to work in the distribution room, an electrician had to pass a test showing that he could get from his bunk to the distribution room and identify any circuit while blindfolded.

The ship's communications took place in radio central, where radiomen received messages that came in from the air, land, and sea.

Radiomen were responsible for typing messages and passing them to supervisors.

Nardi told Business Insider that the equipment in radio central is still operational thanks to the work of volunteers who continue to maintain it.

Coded messages were deciphered in the top-secret code room stocked with three ECM II coding machines.

Canvas bags with lead bottoms were kept in the code room just in case any top-secret information had to be thrown overboard if the ship was compromised.

Even after spending most of the day at Battleship Cove, there was still more of the ship I didn't get to see.

Even with a map of the ship and color-coded arrows pointing the way, touring the USS Massachusetts was a dizzying experience full of ladders, hatches, and tight corners. On a battleship that big, there's an endless amount of history to learn.

Nardi told me that touring historic battleships like the USS Massachusetts can provide insight into how modern Navy ships operate.

Basic navigational equipment looks and works largely the same as it did on World War II battleships, Nardi said. Some communication devices, such as sound-powered telephones that harness the electricity generated by the user's voice, are also still widely used.

"I hear Navy personnel come on board and say, 'Oh, that hasn't changed much,'" Nardi said.

Battleships became obsolete as missiles took precedence over large deck guns. President Donald Trump wants to bring them back.

In December, Trump announced a new "Trump-class" of ships, referring to them as "battleships," as part of his plan for the US Navy's new "Golden Fleet" to reinvigorate American shipbuilding. White House deputy press secretary Anna Kelly previously told Business Insider that Trump is "prioritizing this vital industry to strengthen our country's economic and national security."

However, the Trump-class ships would not technically qualify as battleships. To earn that title, they would have to be the largest, most heavily armored ships with the largest guns relative to other ships.

"The word 'battleship' can be used very generically, which is not accurate. We don't have them anymore, and President Trump's not going to build battleships. He's calling them that, but a battleship is what we have over here," Nardi said, gesturing at the USS Massachusetts floating in the Taunton River. "That's a real battleship."