I went on a $19 river cruise around London. If you have less than a day, it's a great way to see the city.

• I recently went on a 40-minute London Eye River Cruise for $19. 
• I saw the London Eye, the Palace of Westminister, Shakespeare's Globe, the Shard, and Tower Bridge.
• I learned a lot in 40 minutes, but I'd suggest going to nearby Trafalgar Square too if there's time.

Despite living in London since I was a toddler, I still love exploring my hometown. I typically walk or take the underground, but this time, I paid $19 for a 40-minute river cruise around the city.

The tour I went on (there are a few options from different companies, but I chose one via Viator, a tour-booking platform) set off from the London Eye and headed east along the river to Tower Bridge, before doubling back to its starting point. Londoners often see these boats filled with tourists cruising along the Thames.

But I had never been myself and I wanted to see if it was worth the hype. The short answer: Yes, but only if you don't have a lot of time.

I was surprised by how much I learned on the cruise

As I stepped onto the ship, I was curious to see if a boat could be the best way to see London. The seats were comfy, but the rules on my boat were firm: I sat on the bottom deck of the ship and at no time could I go to the upstairs deck, even when the boat was docked.

We set off from the London Eye pier and headed east. While I couldn't see my tour guide, she was clearly experienced (and funny). 

As we passed the Palace of Westminster, I was pleasantly surprised to hear facts not just about when it was built, but about the UK political system itself.

Despite calling the city home, even I learned a few things while on the tour, including how Lambeth Bridge was a filming location in "Harry Potter and the Prisoner of Azkaban."

We passed famous London landmarks, like the London Eye, the Shard, Shakespeare's Globe, and Tower Bridge.

We also cruised by the National Theatre in Southbank (above), well known for its brutalist architecture. King Charles III said it resembled a "nuclear power station," our tour guide noted. 

I appreciated that the cruise focused on these less majestic buildings along the Thames route. It gave a well-rounded view, not just a romanticized one. 

A plus was that the boat did a circular route, so if a landmark was on the opposite side, once the ship turned around, you could take in the views from your window. 

The cruise is a great way to see the city if you're crunched for time, but it's not the full picture

The cruise I chose was short and sweet — only 40 minutes long. As much as I enjoyed seeing the sights and learning new information, I'm not convinced a boat tour is the best way to see the city. Even if the cruise was longer, I was limited to only viewing buildings along the Thames River.

On the cruise I chose, I also wasn't given the option of a tour in another language when onboard. I'd recommend that anyone wanting to do these tours themselves should first research the companies and their offerings.

But for someone on a time crunch, booking a boat tour is a great option. You see famous landmarks and learn some insightful facts via the tour guide. Plus, the cruise was faster than walking and you're sheltered from the crowds of other tourists. 

If you have a few hours to spare afterward, I'd recommend strolling around Trafalgar Square, which was a 14-minute walk from my pier. There are great food options, the National Art Gallery for some culture, and other well-known areas like Leicester Square and Piccadilly Circus nearby.