This is true happening, and a very much personal experience. I am a conservative person and strongly believe in our ancient Vedic Civilization. As a religious person, I have a deep desire and habit to go to a Shiva temple, possibly old one, and do Rudrabhishekam. A small group of we like-minded friends wander and do Rudrabhishekam as and when possible.
There is a place called Aadi Badri, located in Village Kathgarh area of District Yamunanagar, Haryana in India. It is at the foothills of Shivalik region, and full of vegetation. This place was in news about 4 years back regarding Saraswati river (http://shribadrikedar.blogspot.com/2015/05/1.html). Sarawati Water was found in the nearby area.
As I said, we preferred older temples to do Rudrabhishekam. So as a result of our search, the divinity made us reach to this place (http://shribadrikedar.blogspot.com/2012/01/first-visit-to-shri-aadi-badri-nath.html). It was year 2009.
There are temples of Aadi Badri, Shree Kedarnath, Sarasvati River Origin and Maa Mantra Devi. All these are situated along the bank of river Soma, which is a tributary of Saraswati river. Until 2009 these temples were taken care of and managed by the Sanyasis and Pandits belonging a Math called 'Math Machhli Bandar'. This Math belongs to Aadi Guru Shankracharya (parampara) tradition and has head office in Varanasi. In the year 2009, the government took it over. This is unnecessary interference in Hindu affairs, but we have to live with it.
We visit this place frequently to perform Poojas. This is highly energised place due to Sadhna done by those Sanyasis of Shankracharya parampara who took care of these temples over centuries.
During one of such early visits to this place, while roaming along the bank of Soma river, we found a very small temple like structure having a beautiful Shivalingam inside. Its base part was crafted as a blooming lotus. It naturally attracted all of us. Obviously, we decided a date there and then for performing Rudrabhishekam on this Shivalingam.
So, on the decided date, we reached the spot early in the morning. We started with cleaning the entire place. And then started Rudrabhishekam as per the procedure. We do it ourselves. Since it is a jungle type area, there are a lot of monkeys around (that's one reason how the name of Math was formed).
To our dismay a small group of monkeys came near the Shivalingam where I was chanting Rudrashtadhyaayee and others were showering water through Shrringi. A baby monkey came and sat in the lap of one of my friends who was sitting close to Shivlingam. The baby monkey, very calmly, sat in his lap for about 15 minutes without disturbing anything. Initially we were little apprehensive, but we continued with our Poojan. The parent monkeys and their other family members were sitting at a small distance from us. After 15 minutes, the baby monkey left as if nothing had happened.
After completion of Rudrabhushekam, all of us were discussing this. Our little brains could conclude that it was blessing of Hanuman Ji, who is one of the Rudras of Lord Shiva. Why Hanuman Ji !!!! One because he was a Vaanar who came at the place of Rudrabhishekam and behaved contrary to their natural tendencies. And secondly, we collectively do Sundarkand Paath also (not professionally). So for us it was like a signal of God endorsing our Rudrabhishekam and other Poojans. So we were very happy.
Interestingly, after sometime we came to know that the place where we did Rudrabhishekam, is a samadhi of one of the Bramhaleen Head Sanyasis of Math Machhli Bandar (Math where Fishes and Monkeys also live). This also indicated my past life Karmik connection with that Bramhaleen Sanyasi. Otherwise why would I be doing Rudrabhishekam on a Samadhi (which looked like a temple).
This reminds me a dialogue from the movie Bahubali: शिव के मन में क्या है, मैं क्या जानूँ.
Har Har Mahaadev!!!
