What is the below Rebus indicate?

What are the next two letters in the following series and why?
W A T N T L I T F S _ _

*Hint: Check Puzzle Title

Can you count the number of triangles in the given picture?

Solve the puzzle by telling what does below picture means.

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

If you drop a 15 kg iron bar and a 5 kg bag of cotton from a height of 50 meters which will reach the ground first?

In the figure, you can see nine stars. What you have to do is connect all of them by using just four line and without lifting your hand i.e. in a continuous flow.

How many bricks does it take to complete a building that is 15 feet wide, 30 feet deep, and 12 feet tall made of brick?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

Can you solve the below geography rebus by decoding the below rebus ?