Luxembourg's government has abolished fares for all trams, trains and buses across the entire European country.
The scheme applies to all Luxembourg residents - who number about 614,000 - as well as cross-border commuters and tourists.
Luxembourg's Deputy Prime Minister Francois Bausch said the plan would reduce congestion in the capital, Luxembourg City, and cut pollution.
"The main reason is to have better quality of mobility, and then the side reason is clearly also environmental issues," he told Reuters.
"For people with low incomes or the minimum wage, for them it's really substantial."
It's not the first city in the world to introduce free transport - that was Talinn in Estonia in 2013 - but it's the first country to roll it out nationwide.
Why make it free?
More than 200,000 people commute to Luxembourg city each day for work, from neighbouring Germany, France and Belgium.
And with a population growth rate amongst the highest in Europe at three per cent, the government has made improving mobility a priority.
It aims to get 20 per cent more people on public transport by 2025, and cutting down cars on the road by 15 percent.
Making the network free is part of that plan, alongside improving bike lanes, overhauling bus routes, and expanding tram lines and railways.
"The introduction of free public transport is an important social measure. You could describe it as the social icing on the cake of the global strategy for a multi-modal revolution," Mr Bausch said.
How much will it cost?
Before March 1, public transport cost Luxembourgian commuters €440 annually (£380), or €4 (£3.50) for a day pass. Commuters still have the option to purchase first class tickets on trains for €660 (£572) or €6 per day (£5.20).
Running the publicly-owned transport network costs the government €500 million (£435 million) a year, and ticket sales recouped about €41 million (£35 million), or 8 percent of that.
Luxembourg's government has said that's an acceptable amount of revenue to lose, and has already been taken into account in the national budget.
It says existing staff won't lose their jobs, but their duties will pivot from checking tickets to 'passenger service and safety.' Eight smaller train ticket offices will be closed, however.
Despite the investments in making public transport more attractive, the government still forecasts about 65 per cent of commuters to get to work by car by 2025, compared to 73 per cent in 2017.
According to Eurostat, Luxembourg has the highest number of cars per person in the EU - with 662 cars per 1,000 people in 2016.
Its rail network has also been plagued in the past by unreliability, with about one in 40 trains failing in 2017.
With a €3.9 billion euro investment in railways over 2018-28, the country hopes to cut down on train failures and reduce waiting times for more services to less than six minutes.
To sweeten the deal for stubborn drivers, the transport ministry have promised to make sure express buses will beat private drivers to their destinations during peak hours.
About half of the increases are regulated by the government, and the other by train companies.