#include <bits/stdc++.h>
#define rep(i,a,b) for(int i=a;i<=b;++i)
#define per(i,a,b) for(int i=a;i>=b;--i)
#define forr(i,a) for(auto i:a)
#define rall(a) rbegin(a),rend(a)
#define all(a) begin(a),end(a)
#define pb emplace_back
#define int long long
using namespace std;
int p[70];
struct read
{
    static const int M = 1 << 23;
    char buf[M], *S = buf, *P = buf, c, l;
    inline char gc() { return (S == P && (P = (S = buf) + fread(buf, 1, M, stdin), S == P) ? EOF : *S++); }
    template<class T> read &operator>>(T &x)
    {
        for (c = 0;!isdigit(c);c = gc()) l = c;
        for (x = 0;isdigit(c);c = gc()) x = x * 10 + (c & 15);
        return x = (l ^ 45) ? x : -x, *this;
    }
}Cin;
void get(int x)
{
    for (int i = 63;~i;--i)
    {
        if (!(x >> i))continue;
        if (!p[i]) { p[i] = x; break; }
        x ^= p[i];
    }
}
void solve()
{
    memset(p, 0, sizeof(p));
    int n, ret = 0, x; Cin >> n;
    rep(i, 1, n) Cin >> x, get(x);
    per(i, 63, 0) if ((ret xor p[i]) > ret) ret ^= p[i];
    cout << ret << '\n';
}
signed main()
{
    cin.tie(0)->sync_with_stdio(0);
    int _;for (Cin >> _; _--; ) solve();
    return 0;
}