The Panama Canal recently turned 100 years old, but even after all of this time, it still stands out as one of the true engineering marvels of the world. While it frequently tops the “must-see” list among visitors to Panama, the Canal also plays a hugely important role in Panama’s history and the lives of Panamanians. Whether you are preparing yourself for a visit or just want to admire the Canal from afar, here is a list of 23 facts to know about the Panama Canal.

1. The French first attempted to build a canal through Panama in 1881. However, due to a high number of deaths and other issues, they abandoned the project in 1889. The United States started construction on the Panama Canal in 1904 and completed it in 1914.

2. The US began negotiating the rights to build a canal with the Colombian Government when Panama was under Colombian rule. When negotiations fell through, The US Government and President Theodore Roosevelt encouraged the Panamanians to revolt and declare independence from Colombia. Panama declared its independence on November 3, 1903, and the USS Nashville was deployed to prevent Colombia from interfering with their independence.

3. After declaring independence, Panama granted the US control of the Panama Canal Zone through the Hay-Bunau-Varilla Treaty. The US paid Panama a one time sum of $10 million for the rights, as well as a yearly lease.

4. Over 25,000 people died building the Panama Canal, mostly from disease. Approximately 20,000 died when the French attempted to build the canal, and over 5,000 died when the Americans successfully built the canal.

5. The first ship passed through the Panama Canal on August 15th, 1914. The Canal recently celebrated its 100th birthday on August 15th, 2014.

6. The US operated the Panama Canal from its opening in 1914 until December 31st, 1999, when full control of the Canal was handed over to Panama as part of the Torrijos-Carter treaties, which were signed in 1977. From 1979-1999, Panamanians were given increasing responsibilities for canal operations, until full handover.

7. The Panama Canal operates using a system of 3 locks. In order to cross from the Atlantic to Pacific (or vice versa), ships must travel through Gatun Lake, which is 85 feet above sea level. The locks raise and lower the ships from sea level in order to travel the lake.

8. The Panama Canal has 3 locks. The Miraflores and Pedro Miguel Locks on the Pacific Side, and the Gatun Locks on the Atlantic size.

9. Ships pass through chambers in the locks that raise or lower the ship approximately 28 feet. The Miraflores Locks have two chambers, the Pedro Miguel Locks have one, and the Gatun Locks have three chambers.

10. It takes ships on average 8-10 hours to travel the Panama Canal. This compares to 2 weeks if a ship tried to bypass the canal and travel around South America.

11. Only Panama Canal Pilots working with the Panama Canal Authority are able to captain a boat through the Panama Canal. When a ship enters the canal, they are boarded by a pilot, who has full control over the boat until it exits the canal.

12. The locks each have two lanes that allow multiple ships to pass through at a time, but they cannot handle large vessels going opposite directions. In the day time, the direction of the locks are switched every 6 hours and priority is given to larger ships. This way large ships can complete their journey in the 8-10 hour timeframe. At night, two way traffic accommodates smaller ships.

13. All tolls for the Panama Canal must be paid in cash, and must be paid at least 48 hours in advance.

14. Ships (with a few exceptions) are charged a toll based on their weight. The average toll for a ship to travel the canal is $150,000, but it can get much more expensive for the largest ships and additional surcharges.

15. The cheapest toll ever paid to travel the canal was 36 cents in 1928 by Richard Halliburton, who swam the length of the canal.

16. The most expensive regular toll was paid by the cruise ship the Norwegian Pearl, which paid $375,600 to cross the canal. UPDATE: With the opening of the new, larger locks as part of the canal expansion, this record has been significantly broken, as much larger ships can now pass through the canal. As of July 6th, 2016, the new record is held by the MOL Benefactor, a 10,000 TEU cargo ship which paid $829,000 to transit the new locks. It is expected that when a post-Panamax ship (which can hold up to 13,000 TEU of cargo) transits the new canal, that the record toll will pass $1 million.

17. You can take your own private boat through the canal for a fee ranging from $800-3200. You will share locks transit with a larger ship, since it is not affordable for the locks to be operated for this cost.

18. 13,000-14,000 vessels pass through the Panama Canal each year, at a rate of about 35-40 per day.

19. The 1,000,000th ship to pass through the Panama Canal was the Chinese freighter the Fortune Plum, which passed through on September 4th, 2010.

20. Ships specifically built to the largest specifications possible to transit the current locks of the canal are called Panamax ships. The can be a maximum of 950 ft long, 106 ft wide, and hold the equivalent of 5,000 20 ft shipping containers (TEU).

21. A second set of locks are currently being built to accommodate larger ships. When finished, they will operate simultaneously with the current set of locks and be able to accommodate ships over twice as large (13,000 TEU vs. 5,000 TEU). The new locks are expected to be operational in the beginning of 2016. UPDATE: The expanded Panama Canal locks were officially inaugurated and had their first transit on Saturday, June 26th, 2016.

22. The Panama Canal takes in about $2 billion a year in revenue, and approximately $800 million goes into Panama’s General Treasury each year.

23. The Miraflores Visitors Center at the Miraflores Locks is open from 9am-5pm each day. Access to the visitors center costs $15 for visitors and $3 for Panamanians and Permanent Residents.