slave marriages were legal in the eyes of the slaves. but to the slave holder, the marriages may not have even existed. slave owners had the ability to separate the married couple at his will. so in a sense, yes they were, yet in another sense, no they weren't.
No riverboat marriages are illegal.
Yes. There are Christian churches in Israel and Christian marriages are legal in Israel.
No
yes
No. There is no legal recognition of such marriages in Egypt.
No. There is no legal recognition of such marriages in Kyrgyzstan.
No. There is no legal recognition of such marriages in Kosovo.
No. There is no legal recognition of such marriages in Chad.
No. There is no legal recognition of such marriages in Indonesia.
No. There is no legal recognition of such marriages in Estonia.
No, slavery and the slave trade are illegal worldwide under international law. However, forced labor and human trafficking still exist in various forms, despite being outlawed. Governments and organizations continue to work towards eradicating these practices.
Yes, in Thoreau's time it was legal to own a slave.