I was, still am, a freemason, but have been inactive for 15 years.
To become a freemason you must have a belief in a 'supreme entity' not necessarily the christian god, or any god, but some sort of controlling force behind the creation of the world.
Freemasonry is prevalent across much of the world; membership is not denied to any religious, or non religious person... though in england many members are christians, I am sure in india many members will be hindus, etc.
There are some associated orders, within freemasonry, that are based on the christian religion, with great emphasis on biblical teachings.
The fundamentals of freemasonry are brotherly love, relief and truth - friendship between a like minded body of men, who donate and raise funds for charitable work, and are honour bound to be truthful in their dealings.
An example: when the tsunami hit the asian coast at christmas some years ago the freemasons were able to pledge £several million to the international red cross within 30 minutes of news breaking allowing a relief effort to begin immediately.
Hope this gives some clarity.
PS sent many freemasons to his concentration camps.

If you're a 32nd degree Mason then you'd know better than I would what it's based on, both in theory and in practice.

When the ‘opportunity’ was first proposed to me … I asked what the “G” in the middle of their emblem meant.. “If you don’t know that,” “You’d best not apply” was the answer I got. “Secular in nature”? ..I don’t think so

FreeMasonry is secular and not based on biblical principles and as you are most likely aware allows Jews, Muslims, Buddhist. and all other systems. Of the two offshoots. Scottish & York rite, The York rite does incorporate Christianity where the Scottish rite is universal. Freemasonry is a great group !

My mom's dad was a Mason. Mom said when she was young,,,the 1920s and 30s, she was sure the Masons were involved with the KKK. All Protestant men. And she remembers a cross burning by the Catholic church in her small community which coincided with the night the masons met. She said she found my Grandfathers KKK robe in his closet once. We were also told , as Catholics growing up, that we were not allowed to join the Masons or the Eastern Star, because they had secret oaths, etc, that the catholic church did not allow.

I never really paid attention to it, but most of the freemasons that I've known were religious. Where there are believers, there is religious influence. Outside of that, I've always thought the mysticism and secrecy was a bit cultish.

I was approached to become a mason, gave them Groucho Marx's reply (which has always fascinated me) “I don’t want to belong to any club that would accept me as one of its members.”

Actual masonry has existed since long before the bible was ever conceived by men.
When humans were still living in caves, and then began the process of building with stone.

Guilds were later created when masons were needed to build castles and churches.

Some of the guilds joined together as fraternities of stone workers during the Middle Ages, and were thought to be influenced by the Knights Templar.

Even when things start off as secular, religion has a way of influencing and corrupting everything.

[yorkrite.com]

Both with mystical backdrop

My dad was a Mason...it was just a bunch of guys doing a lot of social stuff ...it was silly in some ways, but it bonded them just like a sorority or fraternity...there were all sorts of men in different faiths...I think it was just a chance for my dad to get away from the females of the house for a bit of drinking, smoking and bawdy talk...they also had scholarships and sponsored the little league baseball in our area...

Is it still around? I have his pins and odd things that I kept when he died...

The only Masons I ever paid attention to were Jackie and Perry.

The first rule of Fight Club is you don't talk about Masonry.

I thought it was based on brick-laying....

Seriously, now, I think it might have some religion in it. I don't know much about the Masons, except that I used to be a Moron (oops, Mormon), and the founding prophet, Joseph Smith, seems to have taken some concepts from Masonry and included them in the Moron (oops, Mormon) temple ceremonies. There are robes, handclasps, hand signals, etc. I don't know if they were religious to begin with, or if Joseph Smith just mixed Masonic secular stuff with his religious views.