Through out the world, every where, whenever researchers find shiva lingam from earth, they reach to the decision that hindu people may lived here before some time.
Shiva lingam is found from Russia, Africa, Afghanistan, Ireland, Greece, Mongolia, Siberia, Rome, Sri lanka etc. <- Search on internet about their photos taken from archeologists...
There is a Ancient Shiva temple in Tashkant, Uzbekistan. Ancient Vishnu Statue was found in Russia. Shiv Lings are excavated in Italy. There is a Hindu Temple in Baku, Azerbaijan. Is God Shiva not the Principle Deity all over SE Asia till Phillipines.
Shiva in Islam
Islam also considers shiva as god, in macca there is a shiva lingam whom they call Noor-e-ilahi, noor means light, we call the same jyoti, and ilagi means god, Jyotirlingam or noor -e ilahi.
Shiva in christianity
In church you will find candles, christ said God is light, the shape of candle's fire is the same shape of shivalingam, we call it jyotirlingam, jyoti means shape of fire.
Shiva in Sikhism
In sikh, guru said, Shiva is maha guru.
Ancient Shiva Temples
Do you know that Tang Dynastry in South Eastern China worshipped God Shiva. Japan too worships Ganesha,Shiva, Yama and Saraswati.
Search on internet, you will find many evidence from archeologiests....
America and Australia were not discovered, so they both left....
Also Note: Vedic Deity's are present in many other religions, just names changed.
For Example:
YamaDev or Yamraj in hinduism and budhhist
Yima in Zoroastrianism
Yan in chinese
Yanluowang in japanese
Shinje in Tibetian
Ymir in Proto-Germanic
Hades in greek mythology
Yima Xšaēta in Iranian mythology
Orisis in Egyptian