An American nightclub called 'The Coconut Grove' had a terrible fire in which over 400 people died. A simple design flaw in the building led to a high death toll. Subsequently, regulations were changed to ensure that all public buildings throughout the country eliminated this one detail, which proved deadly. What was it?

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

The answer I give is yes, but what I mean is no. What was the question?

A boy and a girl are sitting on the porch.
"I'm a boy," says the child with black hair.
"I'm a girl," says the child with red hair.
If at least one of them is lying, who is which?

What's the only room from which no one can enter or leave

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

Count the number of squares in the picture below.

Decode the below four famous ciphers:

8P of the SS
1M of the E
1S of the SS
60M in 1H

Identify Me

Hint1: I am a god
Hint 2: I am a planet
Hint 3: measurer of heat

In the Mexico City area, there are two Houses H1 and H2. Both H1 and H2 have two children each.
In House H1, The boy plays for Mexico Youth academy and the other child plays baseball.
In House H2, The boy Plays soccer for his school in Mexico and they recently have a newborn.

Can you prove that the probability of House-H1 having a girl child is more than that of House-H2?