The best invention - Solar panels

In my opinion the best invention of all time is the solar panel. The primary reason for my choice is that it is an eco-friendly solution to heat our homes. In other words, it uses renewable energy, so we can reduce our carbon footprint, might contribute to a sustainable future and can avoid using fossil fuels which will not last forever.  Another reason is that we can save a lot of money because solar energy is free. In the long-term it is more economical to depend on the sun which will never increase its price. Fortunately, these panels are being modersined day by day. The latest models can store energy for nighttime and rainy days, too. What is your favourite invention? Please share your opinion with me and your classmates.